Pour over Youtube videos for more information. I have discovered a variety of different variations in construction but mostly there are common consistencies with most slide seals. the flaps that are around the slide frame on the camper body, the seals attached to the slide itself. none should be torn or damaged.
Clean and treat them with the appropriate chemicals made for them available easily at most RV dealers.
Even if the seals are in good shape and you still have a leak, it could be coming in from a misaligned slide or leak from a ceiling or floor.
You have to start digging. Good luck