As Oli says, accepting the answer is thanks enough (and an upvote if you can). You can thank the community by continuing to participate here: asking, answering, editing — all welcome.
You can ask as many questions as you want, as long as each post is limited to a single question, or a set of tightly-coupled questions - when in doubt, make separate posts.
As for etiquette:
- A bit of diligence in searching will always be welcome. The site's own search functionality is OK-ish, so you could search using Google as well, by specifying
site:askubuntu.comalong with other terms. - Be clear and specific in your question. Phrases like "did not help", "did not work", "tried everything" are meaningless. Post what you did, and what happened, exactly.
- Prefer text to screenshots when reporting errors from the command line.
- Read How do I ask a good question?
