Ihave 3 scsi hds and i just bought another computer that was runnin scsi.Never hooked them up before if someone could take the time to explain to me how to go about gettin them to read in the bootup ie: boot 0 boot 1 boot 2 etc.. And where the pins need to be set on them and in what order

thank-you

Go to Google search, and type in SCSI Drive Installation Guide where you will get lots of results with pictures and diagrams.
If the drivers are by different manufactures, they may be different, you can work it out. Also, every manufacturer of SCSI drives has instructions and images online.
This is just not a good topic to attempt assistance here... too many options... too much time... too difficult to describe what you can see on the manufacturer's site.

generally you daisy chain them and set the switchs on the bottom to go from 1 to 8 in the order they are on the chain (and how you want them to boot)