The swingarm pivot adjust bolts will apply force through the bearing collars and onto the engine cases. The bearing collars are what centers the swingarm axially with the engine cases.
The right swingarm pivot adjust bolt is torqued and locked first, as that's where the pivot ball bearings are located to position the swingarm and control axial and radial movement.
Then the left pivot adjust bolt is torqued using the swingarm pivot bolt, and then locked.
It's all in the procedure in the service manual.
What might occur is the pivot bolt may be corroded and hard to remove if it's never been removed before. That was my case.
I used a rubber mallet and drift punch to gently hammer it out, then cleaned it all up and applied grease to the bolt prior to installation.
Had to clean up the adjust bolts as well.