Unfortunately, I only have a full license for ANSYS 2020 R1 and the Student license I use for ANSYS 2020 R2 does not let me edit the geometry.
You need to open DesignModeler, use Explode Part on the Bolts part. Pick the four Bolt 1 bodies, then Form New Part. Repeat that 7 more times. Now you have one part for each bolt instead of one part for 8 bolts. That will let you do Bolt Pretension. If you do that, you can attach a new archive since I won't need to edit the geometry again.