How do I delete a post or mark it SOLVED?
To mark a thread SOLVED, edit the thread’s original post in Advanced mode. You should see a dropdown menu labeled Prefix. By default, that’s left unset. But you can change it to Solved if your issue has been resolved. Note that this feature is only available on threads in the Support forums.
As for deleting, unless it’s the last post in a thread and you posted very recently, posts can only be deleted by moderators. If you wish for a post to be deleted, use the Report Post feature (it’s the triangle icon at the bottom left of every post) to let the moderation team know.
Okay… how do I edit a the thread’s original post? I cannot find that anywhere.
If you’re the original poster, then you should see an Edit Post link at the bottom right of your post, just before the reply links (Reply and Reply With Quote)
Thanks! That helped me find the edit function. Found the advanced edit button, but… no prefix dropdown 
Can you post a screencap?
In which sub-forum are you trying to do this? Not all forums use the Solved prefix (for instance, it doesn’t make much sense in any of the Artwork forums).
I’ve since figured it out, entirely owing to your response 
I thought I’d posted here to thank you, but it looks like I forgot Sorry, and thanks again!
Not a problem. Glad you were able to figure it out.