I am a professionally-certified astrologer (P.M.A.F.A. from the American Federation of Astrologers), with over 40 years experience doing consults and teaching astrology. Retired now (no new ciients).
The purpose of websites is to generate money.
By having an advertiser linked to their site, who pays them for the number of visits. Or by selling you computer-generated reports (which just have the same information that is already available for free on the internet .. the computer program only spits out that info that is in YOUR chart)..
They are not in the business of teaching you to understand astrology, but to keep you dependent and somewhat confused. This brings you back to their site over and over, and often prompts you to cough up some money for a computer generated report.
Books are a better source. Of course, books too are doing it for the money. But astrology books are usually accepted/rejected for publication, on the evaluation of whether or not they will sell. And the major "market" for astrology books is the world of astrologers (both the pros and the hobbyists).
Some books are just popular astrology (Linda Goodman made a fortune from "sign-astrology) during the decade astrology was pop-culture). But many books are serious astrology and have value.
So you buy the book once (I recommend amazon.com or alibris.com, since second-hand books are much cheaper .. and amazon.com has "reader reviews" for many of the books they sell).
Now, the way to do chart interpretation is to learn the theory.
What part of the personality each planet represents.
The styles of behavior for each sign .. both the positive and the negative sides of each sign.
What area of life each house represents.
And what type of internal interaction between needs, is shown by each of the major aspects. Because the aspects are what sets our personality into motion .. those inner needs that work together smoothly,, and those that contradict each other. This is what creates our behavior, and the sign for that planet is just a list of possible styles of behavior .. constructive or non-constructive depending on how that planet/need operates. And in whatever area of life, represented by whatever house the planet is in.
Once you have the theory down, it is just a matter of envisioning how those needs interact.
Say Tyler has Moon in Taurus and it is square Mars in Leo.
Moon is our emotional reactions, and how we try to handle our emotions in a way that feels safe/comfortable to us. In Taurus, this is an attempt to be placid . to NOT be rocked by changeable emotions.
Mars is how we go after what we want, and how we react when our desires are blocked. Leo is a proud and firey sign, full of enthusiasm, but also quick to take offense ... a fixed sign that is not very adaptable.
The square aspect shows discord .. so YOU think about it ... HOW does an emotional need to be placid conflict with a need to enthusiastically go after what you want without being flexible about it .. with being proud and given to taking offense if contradicted by others?
Can you see how this creates problems between their emotions (Moon) and their way of being assertive (Mars)?HOW they go about getting what they want (Mars) create emotional instability (Moon-Taurus) for them, and they NEED emotional stability.
Moon square Mars always indicates a conflict between emotional needs and assertiveness needs .. and the signs help pinpoint just why there is this conflict.
So this is how astrologers do readings without a reference book, without someone else's written interpretations. . They learn the theory, and like stringing beads to make a necklace, they put together the dynamics of how the inner person operates.
But this is also why astrologers only do readings in a real-time format (in-person, over the phone, on Skype) .. because we may be the experts on what the chart factors mean, but the SPECIFICS of HOW those factors work together ... well you are the expert on what is going on inside of you.
The astrologer says "yada yada yada means that you feel ... or ... or ....) and the client says yes or not or well maybe but it works more like THIS. And the astrologer says, well that's not what that aspect is indicating .. but this aspect over here could work that way.
TOGETHER the two come to an understanding of how the personality dynamics are interacting. The astrologer has the general picture, but the fine-tuning comes from the client's participation.
As far as books go, I used to recommend "The Astrologer's Handbook" by Sakoian and Acker as a basic introductory book. But you get limited information from "cookbook" approaches (Sun in this sign + Sun in that house + Sun trine Jupiter) because no book can put it ALL together into how it operates as a whole. YOUR brain has to do that. The "cookbooks" are only a starting approach and the more you rely on them to give the picture, the less you see.
I also recommend "Planets in Aspect" by Robert Pelletier ... he discusses the different natal aspects, in a psychological perspective ... what DRIVES the person. Which is how we arrive at an understanding.
As far as other books, you are looking at theory .. not cookbooks. I found Dane Rudhyard was an AWFUL read ... very pedantic,, and I would have to read and reread every paragraph over and over just to figure out what he was trying to say. But as I slogged through his books, gradually I began to see the theory of the patterns of astrology .. what underlies all the interpretatins.
Tracy Marks and Stephen Arroyo are also good.
Distance lessons are useful, I understand. American Federation of Astrologers has distance learning.
IN-TOWN lessons, if there is an astrologer who teaches in your town .. these are great. And if there is an astrological society in your town, that is very useful. The best place to START tracking down these resources is at your local New-Agey bookstore. Or google "professional astrologers" or "astrological organizations". AFA, ISAR (International Society for Astrological Research), and NCGR (National Council for Geocosmic Research) all have posting of professional astrologers ... if there are any in your town, try contacting them to see if they teach or know any local teachers.
Understand that the chart is only an influence on us. Sort of our "default" setting, and the more self-aware we are, the more we know how to change our default settings. And that the chart is very good for indicating internal dynamics, but not so accurate for external behaviors .... we all have the ability to choose our external behaviors (to override automatic knee-jerk reactions and instinctive responses). Astrology helps us become more self-aware, and the more self-aware we become, the more we are the major influence on our selves, and the less astrology is.
So the purpose of astrology is to operate as a base of operations, a list of suggestions, from which to undertake our self-exploration.
“All anyone can see in a birth chart are tendencies that will become facts if the person does not do something to alter them.” (Isabel M Hickey)
If you are looking for surety and predictability in life, and if you hope that astrology will always be right .. you are going to be disappointed. Many times astrology fits very well ... even to the point of being Statistically Significant ... but nothing in life is guaranteed nor is there anything that is unfailingly accurate in predicting.