mk1 cabrio> audi a3 motor swap (2H>AEH)

hello

sorry for bothering but i did not found anything similar here

So, i am the owner of an old Cabro, with 2H egine, but latelly the motor is not running good
anymore,so i bought an completlly crashed Audi a3 with an AEH motor, but motor is still in the car and running

I bought this completlly car for 100€, which is not so much, and now i would like to make a swap
as i have the whole donor car, i think that will not be a problem, but i need some help and info.

what should i be carefull for, any links maybe, everything is welcome

Thanks for help