Change V-belts

Hello first of all, I have a V70, year 2001 with LPG system and 220,000 km on the clock since yesterday. I noticed two things, for which I would need tips: The servolankung is sometimes too difficult, e.g. after a longer motorway ride. Oil is enough in it, I think it is due to the pump. But I don’t even know how to get down the rib belt. Where does it get relaxed or relaxed? And how do you get there? (Obviously, because I’m not an inexperienced screwdriver in itself). Then ma But I can’t locate where the noise comes from. The TÜV man could not tell anything. Does anyone have any experience with it? How long do the things last? When do you switch them for safety reasons? Then I would like to have a workshop manual for the V70 (2.4), someone knows what? I had that from Haynes for my 945, was quite okay. I say thank you.