I am an absolute beginner in modular representation theory of finite groups. I know some things in representation theory in characteristic zero. My questions are regarding the main goals of this part of representation theory.

For example, does the modular representation theory give information back regarding the structure of the group algebra or of the group itself? I would like to see some specific examples where this theory can be applied. I know that it studies the blocks of the group algebra but I don't know too many things about this.

What are the other applications of the theory? I have seen there are some interesting things related with modular forms also discussed here on the forum. Besides that, what are the other applications of this theory?