Mobile Applications

I talked to this guy that recommended me to look into mobile app pentesting. Does anyone here have some kind of book, course, videos, anything on the topic? So far I’ve googled and found someone who used Burp, however I can only get it to intercept HTTP(s) traffic, and not other traffic coming from the mobile apps. Would love to see how the apps communicates and how to manipulate that. Also found some auto testing, but thats no fun.