E36 seats into e30

[JE1991]

So I'm currently trying to fit some e36 front leather seats into my e30. I've already got the adapter brackets however I can't fit the seats to them still because the bolts seem to be too small in length to come through the holes they are meant for and the seatbelt retainer is stopping the seats from fitting. Anyone know how I'm meant to fit them in and could give me directions??