How do I configure my 80-pin SCSI HDD, to work in a 50-pin computer system ?

I have an 80/50-pin adapter that goes on the back of the hdd, so that I could use 50-pin cable already inside the computer. The hdd is a 18gb SEAGATE "Cheetah" ST318203LC, and the computer itself is a COMPAQ Deskpro ( Pentium 2 MMX type, no visible model number shown ). The adapter also has these jumper pins located on the right side, next to the cable socket, and I wanted know if they any priority regarding the hdd's configuration ?