Maintenance booklet and self-made repairs

Hello, since my OMI has already 105,000 km down and until then there was always a maintenance stamp from the FOH in it, I think to make oil changes and the Klinigkeiten itself. Unfortunately, you only get a stamp if you let the FOH run around the car for an hour and the inspection is processed according to manufacturer regulations. This is meanwhile also the case with ATU, Pit Stop uva… The problem is that I have a not completely guided maintenance booklet, which of course with a possible resale of the OMIS can lead to problems.How do you do it so?Do you have all the completely guided maintenance booklets ? Or no matter from a specific running reading ? Thank you.