IDEA help: how do you use photoshop? - Help.com

Step 1) Read the manual.

Step 2) Understand your need for photoshop.

Step 3) Go here: CreativeCalf.com Photoshop Basics

Step 4) Go here: http://lynda.com/ for in-depth Photoshop training.

If you already have photoshop, just install it and run it. You don’t need to buy anything else for it to run, though there are a few peripherals that make using Photoshop a much nicer experience.

That depends what you want to accomplish. Photo correction? Graphic design? Digital art?

it depends what you want to use it for,i would say learn the basics first,like layering,croping,colour correction and stuff,and learn all the brushes and tools there is,one you got that in your head,thats when the fun starts.
good luck