Redoing Topology??

Hello Blenderartistians!
I’ve heard about redoing a mesh’s topology for, well ever since I begun using blender a year ago. I know the reason as to why you do it, but I don’t know how. I’m currently working on making a tank and I need to texture it, but all the faces are a mess so I need to redo the topology to be able to reasonably UV-unwrap it. The problem is, no matter how hard I look I can’t find anything regarding how to redo the topology. No tutorials, no documentation, no nothing. Help would be appriciated!

TLDR: I want to know how to redo the topology. Links or short tutorials any help is more then walcome!

Thanks in advance!