It will take some considerable time and effort to learn EasyLanguage (EL) but it really is the easiest of the major trading program languages. The great thing about EL is the tremendous amount of educational material and support available. Also, just when you think you have learned everything, you discover a whole new level of complexity available.
Anyway, the best way to get started is the two courses sold by Tradestation. "The EasyLanguage Home Study Course" and "Mastering EasyLanguage for Strategies". A good companion while going through these two courses is "EasyLanguage Essentials" also sold by Tradestation.
Once you have a basic understanding of what is going on, the Tradestation WIKI is a great learning tool, and free.
There are also numerous books that include EL code to demonstrate concenpts from the books. A good one is "Building Winning Trading Systems with Tradestation" available from Amazon.
If you really want to create your own indicators, screens, and strategies it is going to take hundreds, perhaps thousands of hours of study and hard work to get far enough along to start doing cool stuff.
If you are not really that interested in programming, you would be better off to hire a Tradestation programmer to construct any indicator, screen or strategy you can imagine.