How do I find a question on this site that I may have already asked?
A secondary question arises due to my failure to post this simple question. What tag should I use to allow the original question to be posted? I see no list and I have no clues either so my wrist gets slapped if I use common sense with a tag like 'question', because, it seems, I have to know all about tags and have had to have posted three hundred questions before ANY of the tags I tried worked!
All questions that you have asked on this site are accessible for you from your profile. You can navigate to your profile by clicking on your avatar in the top right corner of this page.
The tag that you use for your question can be whatever you like. But the tags won't be come useful unless the tag is related to your question.
In the search bar, type:
<keyword> user:me is:q
... and you'll find all your questions where the keyword appears (your user number appears automatically)
To get all your answers with the keyword, type is:a
Searching for tags to tag a question sometimes requires a certain amount of trial and error, but in this case finding the right tags for your question was not difficult. tag was an obvious tag to start with because of the high probability that someone already asked a question at Ask Ubuntu Meta related to this tag. Surely the volunteers who help to create new tags wouldn't be likely to have not created other relevant tags like search and profile-page either.
By the way you can hover the mouse over any tag including the tags in this answer to show information about the tag.