a primary qustion

If I want become a professional in 2D animation, which products I should learn in sequence?
first …?
second …?
third …?


I guess it depends what you want to do in the Animation field. This being said be aware that for animation the best thing you should be working on is your drawing skills. The tool that is used afterward will just help you out with production time and such.

If you want to get some basic tools you can start from Flip Boom/Animation-ish to more complex tools afterward such as Toon Boom Studio and go up Animate Pro. Concepts in our software are similar so after you get a hang on the basic things those things usually apply on the rest of the software.

Best regards,