The next step after the Basics

Answer 1

Keep using what you learned to write the desired app you want, i recommend you to pick up books and other courses to extend the knowledge as sololearn is not very extensive.

Answer 2

html5 css3 jQuery!

Answer 3

Try to make some apps or games and always practice ....
here's some Websites that you can practice coding..

http://www.thecrazyprogrammer.com/2015/02/top-10-websites-to-improve-programming-and-coding-skills.html

Answer 4

I am really interested in builiding websites and design and also making games