Hi @edwardsun55. I'm a novice myself but here is what I understand.

• When you buy a share of SBI you get a share and the person you nominate get a share.
• I do not know whether you can nominate yourself and therefore get two shares.
• Whenever you buy a share or receive a share from someone else that share gets added to the number of shares you own. The upvote you receive then increases accordingly. There are Google docs where you can search your name and see how many shares you have and what the value of your upvote is.
• The value of your upvote fluctuates as do all things on Steemit.