For an RV bed support in my first rig, there was nothing (actually the bed base was screwed down and I turned it into a storage area), I added gas struts for under there. Then on my second RV, the factory RV bed support was so wimpy that it was a pain to lift the bed and it didn’t stay up, so I used the same struts from my first camper as an upgrade.
You need 3 things:
- Ball mount for the bed base
- Ball mount for the portion of the bed that lifts
- Gas strut to make lifting it easier
Because I opted for struts from a car, there wasn’t a guide to tell me where to install the ball mounts. I wish I had a better answer, but mine was “guess and check”. I think there was something to do with retracting it fully and marking or something. But I’m a simple (and not incredibly smart) guy.