How do I move a forum thread to another forum?

Go into the forum thread you wish to move

In the top right hand corner, there’s a drop down box marked: “Move This Discussion To…”.

Select the forum that you wish to move the thread to.

How can I backup forum posts?

Unfortunately there is no easy and efficient way. The only options currently available are:

1. Display discussions in nested form and copy and paste them into Word (would need to be done on a per-discussion basis)
2. Backup all the forums in a course (using the backup utility in the admin block). This produces an XML file from which message data could be extracted but not easily.

1. is easier, though could be time-consuming if there are a lot of discussions in a forum. 

Can I attach multiple files to a forum post?

Yes. You can zip files up and attach the zip file to the post