On Sat, 23 Sep 2017 11:10:17 -0600, rbowman wrote:

For example, I didn't even know the pressure plate had bolts.
The DIYs I found just said "remove pressure plate" so I assumed there were
no bolts.

No, there are a number of them. Both removing and replacing them, you
want to work your way around evenly rather than removing them one by
one. The default position for a clutch is engaged so there will be
considerable spring pressure. The screws themselves aren't big, usually
in the 1/4 - 5/16 range so it won't be a lot of torque.

I see the bolt holes in this pressure plate at time 91 seconds:
https://youtu.be/9UmrCl2nLKM?t=91