Questions about seeding

I'm still trying to understand the bit torrent business...

I just finished downloading a file and now see that it will seed for 1 day and 9 hours. I have three questions -

1. If I click on 'peers' and no one is there, should I continue seeding or wait until people are waiting to download?

2. If I shut down the computer will the file automatically seed when I boot up again?

3. If it doesn't automatically begin seeding, how do I do it on command?

btw - I've tried to read the FAQ about torrents, but get totally confused, so please don't throw stones at me for asking directly.

Thanks, Barry, much appreciated. I think I've got it now.