Papers and Journals?

You do some research, write up the results and submit it.

The editor will send your paper to two or three referees, who will review it (sending you comments), with either an accpetance (subject to revisions) or rejection.

Take the referee's comments on board and improve the paper - even if they recommend rejection. The worst reports I've received are the ones which recommend publication with no revisions (not even typos) required. These don't help anyone.

Tricky one.

Your institution usually owns copyright over your work. However, you do have to sign the paper's copyright over to the publisher. If you want to use the published results you are meant to ask the publisher's permission but it's sometimes quite enough to change style/figures a bit.

No real minimum length. Some journals have a max length, eg. PRL of 4 pages.

Generally LaTex. The journal's website will provide style files.