Seriously. How? How!? HOW!??!??!??!

What kind of software do I use? How do I use that software? How do I get the image file to correspond with what I want it to be associated with? Why won't anything I download WORK!?!?!

.....Okay, maybe they do work, but the programs are so bloody hard to understand that I can't figure out how to resize, tweak texture, etc..

Please help me.