Run SETUP.EXE and follows the installations steps.
After the finish copy the ascan.ma, ascan.dll and directory ascan from usv8\MDLAPPS directory and past in corresponding Microtation's MDLAPPS directory.
For example C:\Program Files\Bentley\Program\MicroStation\mdlapps .
Finally copy ustn.m01 into the c:\Program Files\Bentley\Workspace\Interfaces\Microstation\default.