Playing top lane, around 10h playtime, can you give me some guidance about wave management?

I would like to know a few things.

1. Whats the purpose of freezing and pushing the wave, and when should i push/freeze the wave?

2. How do I freeze/push the wave?

3. How can i get the wave in a gankable state?

Other tips and video tuts you find helpful are appreciated, and thanks for the help!