Sorry, I didn't see all those PM's!!!

[Merlin]

Also, does anyone know how to attach something in a PM?  I can't figure out how to do it, and it's obvious in the regular forum posts how to do it, so I'm thinking it's either not an option, or I'm just a doofus who can't figure it out.  Any help is appreciated!

You're not missing anything, there isn't a way to add attachments to private messages. This has been something on the MyBB request list for at least the last 5-10 years but as far as I know, they have no intention to support it. Maybe they would if more people asked for the feature, but it doesn't seem to be a high priority.

You can fake a file attachment by using a file sharing service (Dropbox or Google drive for example) to host the content you want to send and then supply a direct hyperlink to that content in your private message. But as far as I know, there is no way to do this directly and probably won't be any time soon.