Your imagination is oversimplifying the process. It’s not “this morning I decided to be a terrorist so I signed up for jihad on their website and later that evening I was planting IEDs on tanks”. It’s a gradual process of recruitment and radicalization, testing and evaluation over months or years, with many intermediate steps and countless small tests of loyalty along the way as you work your way into the organizations and then up within them. Trust is not given it is earned. Your first “job” will probably be from someone who acts like they’re just being social and having conversations with you as a friend, and they’ll likely to encourage you to do something like parroting their propaganda on other places on social media, and as you do they’ll judge how well you follow instructions and how resourceful you are and might start giving you hints of other things you can do and see if you take the bait and judge how you react to those suggestions.

Literally no one has suggested that the process is anything like that.

The website/app is probably secondary to being vetted by in-person operatives already receiving money if I had to guess.