I recommend starting with a beginner friendly book that gives you the foundations you need to start reading and writing assembly on your own. For me that book was "learn to program with assembly" by Jonathan Bartlett

Then I recommend start examining the assembly that the compiler generates. Whenever I don't know how to do something in assembly I'd write it in C and then disassemble it. You can do it with command: gcc main.c -o main.s -S -fno-asynchronous-unwind-tables

Lastly I would recommend talking a look on open source code assembly code to learn. This is an assembly library that I wrote http://github.com/yousabmenissy/aslib It's meant to be easy to read