Two things are required in order to read a chart.
An understanding of the parts of a chart, and what each represents.
A basic understanding of how people work inside. Because what the natal chart show is what happens INSIDE a person.
One thing that is NOT very useful, is the internet. The majority of the sites are there to make money. Either they are paid by advertisers who pay according to how many visitors the site has (how much exposure their ad ON that site gets) ... or the webmaster makes money by confusing you and then selling you computer-generated reports (since the info is piece-meal, and already available for free on websites, by PAY for it?).
And a number of these sites are not even run by people who know astrology very well. Same goes for YouTube.
Of course, those who write books are also doing it for the money .. but the primary market is professional astrologers, and editors weed out books that have garbage info. Books cost money to print and distribute, and if astrologers reject the book ...
Best bet find a local astrologer who holds lessons. Preferably one who is certified (AFA, ISAR, NCGGR, Kepler College).
Second best is to read books ... Rudhyar, March & McEvers, Sakoian & Acker, Tracy Marks, Stephen Arroyo, Noel Tyl, Robert Pelletier, Robert Hand ... some of the better books to read.
But MOSTLY is to do chart after chart after chart for everyone you KNOW (celebs are not of much use, since their PR managers control what YOU see). Comparing and contrasting what is I the chart with what the person shows, comparing one Moon-in-Taurus you know with another Moon-in-Taurus and seeing if they match what Moon-in-Taurus is supposed to be like .. and if the ways in which these two are different can be seen as the differences between the two charts.
Expect it to take years.
UNTIL then, learn the theory.
So the parts of a chart:
(1) The planets. Each planet represents a different part of the personality. Dane Rudhyar is a difficult read, but the info you get is invaluable. Especially for the nature of the planets and for the houses. You need to clearly understand what inner need each planet represents, and to be able to understand how that inner need pushes our reactions and responses and behavior. Because your interpretation STARTS with each need.
(2) The aspects between planets. When one planet aspects another planet, there is an interaction between those two needs. If there is no aspect, then how one need operates has no effect on how the other need operates . there is no interaction. But when they DO aspect each other, depending on whether or not that aspect is a harmonious or a discordant aspect, then those two needs work together OR they conflict.
SO what do you think might happen if what you need for emotional security inside yourself conflicts with your social style/the you relate?
What might happen if what you need for emotional security supports and enhances the way you relate to others? And if your relationships support your emotional nature?
This is where you START when reading a chart, and no book can give you an answer.
So you must learn how to find the aspects in the chart, and what kind of interaction dynamic is shown by each kind of aspect.
(3) Once you have determined how this planet interacts with other planets (the aspects), then you have to make a value judgement about how well/how poorly the person finds it to work with this inner need, to try to get this need met.
A harmoniously aspected planet will easily express the positive side of whatever sign it is in. And a discordantly-aspected planet is stressed-out and tend to blow off and express the negative side of whatever sign it is in.
Why? Well HOW that need interacts with OTHER needs (the aspects) will suggest why.
Say that Moon (emotion) square (conflict) Venus (relating) happens between the signs/styles of Aries and Cancer. The Moon in Aries shows emotional reactions that quickly rise up and are openly expressed. The person can get irritated really quickly and flash at someone .. and then be over it.
But they NEED gentle and nurturing relationships (Venus in Cancerr)
Being quick to anger does NOT tend to produce gentle and nurturing relationships with others.
This person will not get the social results (Venus) they hope for, nor will they find their relationships emotionally rewarding (Moon). There will be a lot of inner stress generated over this, and it tends to increase the Moon-in-Aries tendency to be abrupt, as well as the Venus in Cancer tendency to get hurt easily (others WILL react badly to their anger) and then back off.
So you also have to understand the STYLE that each sign is trying to express, and the range of both positive and negative styles.
Take Virgo .. the neat-nicks of the zodiac. Or are they? Virgo is a style of attending to details and making everything "just right". But what happens is their standards are unrealistic and cannot be met, or they lack the confidence to believe they CAN meet their own standards? This is when the neat-nick of the zodiac becomes the biggest slob of the zodiac.
(4) Houses. Areas of life. Whatever house a planet is in, that is where you try to meet that need. Moon in the 4th house gets emotional security and is most-emotional about home and family .. in the 5th, it is over art/children/romance .. in the 9th, their philosophical/religious foundations/beliefs ... etc.
So Moon square Venus, with Moon in the 9th, some of that stress over relationships will probably involved conflicts over philosophical or religious beliefs that they are attached to.
You will run arcross, over and over (in books at least) ... tables that link a planet - sign - house.
These are learning tools.
Moon is our emotional need. It is association with the STYLE of placing value on nurturing, belonging, and family (Cancer). And with the area of life that deals with our early childhood, our parents, our family and our home (4th house).
This does not mean that a planet IN Cancer acts out in the area of the 4th house activities. It means only that you can understand a sign better by thinking about the planet that "rules" it and the house that sign "rules".
So planet/need acts in a sign/style, either well or poorly (aspects), about SOME specific area of life (the house).
The IMPORTANT thing is to look for the strongest part of the chart. Tune in on that and work it out well before moving on to other parts.
Angular planets, stelliums, major aspect configurations (T-squares, etc).
Repeated themes (like my sister who has Sun in Pisces, Neptune in the 12th house, Neptune angular, Neptune square her Moon, and Jupiter square her Sun. This gives a repeated theme that is Neptune-Pisces-12th house in nature and this is the strongest part of her personality). ALL charts have some kind of repeated theme .. or 2 or 3 themes.
So start out with what is strongest in the chart.
And ONLY use the 10 planets . leave out the Nodes, the asteroids, Lilith. Good chart readings don't even NEED those.
And use ONLY the 5 major aspects.
One of the biggest problems is that beginners don't know how to weed out the extraneous stuff .. and this is one way, by confusing beginners, that websites make money selling reports.
More is NOT better in astrology. In fact if you were to throw in everything plus more, you would end up having SO many influences that you could be describing just about anyone. And that is not the purpose of astrology.
Hope this helps.
I cannot do a lot here, because it takes a whole book ... or 2 ... or 3 .. or more.