Comment by twostraws

All you have to do to unlock the next free challenge is solve the previous challenge. The first 10 tutorials are designed to teach the basics of the app – how to transform data with the toolbox, how to read web page source code and run JavaScript, basic Linux commands, etc – and so they are run in order. There are 10 in total, all free, plus another one in the first territory afterwards, which teaches the basics of ciphers.