Replacing Adaptec 39320 controller

I am on a Dell 670 Workstation. I am adding a 1TB "Medea RTR320" external drive via an "ATTO UL4D" card.

 

This is for an Avid editing system. I was told that, for best results,  I must disable the 320 SCSI onboard raid controller and run this internal SCSI on the ATTO also. To do this I must disable to onboard adapter in setup.

 

I am new to this and need some explanation of how to do this. When I start up the pc and hit CTRL A I find the menus for the SCSI's. There are three:

 

39320         A at slot 06 02:0C:00

39320         B at slot 06 02:0C:01

AIC-7901       at slot 00  02:0E:00

 

1.)  Do I disable both 39320 controllers in slot 06?

2.)  Do I disable both SCSI controller Parity and SCSI Controller Termination?

3.)  Following that I assume I install the ATTO UL4D, and physically attach the onboard adapter to the first pin connection on the internal part of the card, and the external drive on the second pin connection on the external part of the card?

 

Thank you.