At least follow the directions on post #1 above.
You cannot learn Photoshop from scratch in a forum, question by question.
As I've typed countless times over the years, Photoshop is a professional level application that makes no apologies for its long and steep learning curve.
Your needs far exceed the scope of this forum.
To start learning, read the Help files; take a class in your nearest community college or similar educational institute, watch the Adobe video tutorials on this site, take a subscription to lynda.com, etc. There are many learning tools out there, just Google "learning Photoshop".
Good luck (and please remember this is a user site. I do not work for Adobe).