Need advice on installing an oil filter adapter

I have never put an angle adapter on so :)
and I have looked for instructions , not seeing any good info on removing the spin on bolt, I know there is a seal behind the plate
The seal is a flat gasket. The machined surface must stay flat.
The Right Angle adapter uses three gaskets:
1. Same as the stamped plate, sealing the outside.
2. Seals the center of the adapter to the block (thick gasket)
3. Under the head of the hollow bolt.

The hard part is getting the clocking so changing the fileter is as convenient as possible. I don't know of any trick for lining it up outside of trial, maybe @krazykuda or some others do.

The K&N filter makes it a little easier, that's for sure.
On my '67, I unscrew them from underneath, face them up resting on the t-bar, then reach down from over the fender to get the filter from the top.
On your early A, you might have to do similar, esp with headers.