I'm such a newbie! An idiot at that too and or blind. Been looking for this opinion, how do I do it??

you cannot do this yourself. Look at the top of the forum where you have a topic you do not want, and ask the MiniMod for a lock. Or, click on the last symbol on the upper right of your first post there, and use that to report your post. A wandering UA will catch the Ticket and deal with it for you.

More sophisticated would be to also choose to Edit it with "ignore please" and edit the title too, or put "lock please" in the title.

Welcome to Subeta! There's a good reason you haven't been able to find that option - it doesn't exist! Older topics/answered questions will eventually be bumped down the page, but if you really want people to stop posting on a topic (or accidentally duplicated a thread or something) you can request that a minimod lock it for you. Each subforum has it's own minimods (listed at the top of the page) that you can ping if needed. :)

lol thanks. I was trying to sell my pet even before I learned the rules. I learned the hard way. dang that sucks! thank you for your time replying to this.