Rotten super slide wood frame

Take a picture of the damage and mark out on the frame that you can keep, where the studs and joists connect. Tear out the rotten frame and replace with new. Plan on some cleanup and not being able to use that area for a few days. There must be a substantial leak in the roof area for the damage to appear suddenly. You'll want to repair that roof area and make sure all the side walls are sealed, as well.

There are some pictures in the "Cowboy/Hilton" link in my signature. If you look in there, you'll see I gutted the whole trailer and rebuilt it. A slide will be much easier. Good luck!

How handy are you with tools and DIY stuff? Do you enjoy doing that kind of work around the house?

Tearing into a wall in either your home or RV is not going to be a quick or simple process that can be directed via a forum without a lot more info on your part, or at least pictures... ;)

I've done rotted framing repair on houses in my younger days when I worked in construction. Not fun or easy, but having a 'Journeyman' guiding the way, the job was done without issue and we fixed the problem that caused the issue in the first place too. I was able to do similar repairs on my own after that and even did it on my folks house to earn a little extra $$ when I was young and inbetween jobs. But I would not want to deal with anything like that now when I can pay someone else to do it now that I'm old! :)

Basically you have to support the structure that is not being ripped out, but bears weight, tear out the rotted stuff, , replace with new stuff and fix the reason for the water intrusion in the first place..

Not trying to be a smart ass, but it's a really open ended question, so the open ended answer... ;)

Good luck with the situation in any case.

Mitch