Can I ask a follow-up question?

Yes. Reply to the answer email, or use the follow-up form under any published answer.

What is the difference between general information and advice?

General information explains how things usually work. Advice applies the rules to your own facts. This site gives general information.

What should I have ready before I ask a question?

A few sentences of background, the dates that matter and the outcome you want. Most good answers start with a clear question.