So I currently only tested using the Reolink video doorbell battery. I have many more battery cameras laying around, but I just did not have the time to check more models.
You should be able to just go to settings>devices>+ add integration>Reolink and then just put in the username, password and IP. Then it should connect. If not, I would need to debug and look into that specific model.
I know that Reolink is working on a improved version of the battery protocol (combining UDP and TCP). I am not sure if that protocol is already in newer Reolink battery models. If so, those models will likely not yet work.
I did not mention this in the docs yet because it is still very much a work in progress. Yes the battery doorbell works, but I have no idea about the other models. Moreover the Motion and AI sensors don't work yet since I need a new push protocol for battery cameras that wake by themselfs. (working on that next). So currently you can see/make snapshots and control settings and things like the lights and siren. But some essential features are still missing.
So I did not want to put it in the docs and get wrong expectations that it is actually feature complete. I will update the docs once I feel comfident it works on most models and the most essential features are all working.