[throwawayrev3]

Start here. Start with the second one - 'From n00b to l33t: An Introduction to Reverse Engineering'.

"This workshop is a 1-2 hour introduction to what reverse engineering is. It assumes no knowledge of assembly and is done on paper worksheets rather than a computer setup for accessibility and to make the most efficient use of time."

It's by Maddie Stone, who's a Security Researcher at Google Project Zero.

She also has Android app reverse engineering

https://www.ragingrock.com//pages/tutorials.html

Later, check out this book:

Reversing: Secrets of Reverse Engineering by Eldad Eilam

https://www.amazon.com/Reversing-Secrets-Engineering-Eldad-E...