Please some one answer my questions related to equities

I want to start equities, and I have SBI savings account only. Can some one please clear my below doubts.

1. We can buy shares from SBI demat accounts? or it helps us to receive and send money money?
2. Which website is best for buying equities?
3. When it comes to sbi demat, what I need to open it? I have online savings banking account already!
4. I need to pay any extra charges to SBi demat ? or its free service?
5. Why we will get loses If we wait until share value will increase?

I know my questions are silly for you, but for me these are very big questions which I need answer quickly :p Some one please answer my questions pls...