Your welcome. Their is plenty of information here to help first time buyers.
On the E36 the odometer has a small dot below the mileage. This is called the "tamper dot". The car stores two sets of mileage data. Of one of the values does not match this dot illuminates. This is to prevent odometer fraud. Do note that I have seen several people legitimately have to replace their instrument cluster. If this is the case they will have documentation proving this. Their actually is a way to reset the odometer to the true Milage, which I would hope most people would do but not many know about it unless they went to the dealer.