How to set Display environment variable

Hi all

We will run sapinst to export the database(oralce).

We do not know how to set the display environment variable.

We will use X window to remote the source system.

The SAPinst GUI will be started on source system.

1.So.Please tell us should we set the display environment variable?

2.if need, Please tell us <WHAT HOST> will be set.

We know the commend[export DISPLAY =<WHAT HOST>:0.0]

Thanks a lot in advance.