Htaccess script for xenforo forum

I need someone to add an htaccess script. I just switched forum software and see a lot of 404s.
The man who fixed my rewrites did some strange things. I d like to clean things up and do a proper redirect.
I worked it out in a word document.
Before starting this project we need to be sure we understand eachother :)
So if you have questions we need to communicate good!

I add a document what i like to 301 redirect.
I added my .htaccess file. As you can see i need to keep a few things like the expires.

I added html.txt (that is html.php), in my htacces that i have right now it forces to open html.php, i added the file so you can see what happens. Its not a nice manner of redirecting so i like remove the html.php