obivously you shove in the adapter on and theres many vids of that online , but how do you meter properly? I realized recently that pk era film lenses and their respective bodies have a little turning pin that pokes out. When the aperture turns, it turns the pin to help give the aperture number to the body to help correctly meter. I mean sure, you can press the m42 lenses button that stops down the aperture, but i still dont get how will help the light meter if it is not being directly told the aperture number in the body. Unless the adapter turns the pin all the way open for metering , and you simply stop down to your aperture to get a readout , but i still dont get how this would work because wouldnt the pin on the camera body detemine change in metering when the aperture is changed?
I cant tell if im being a whiny ass bitch and overthinking it and it will be fine when i get an adapter or if i will need to buy an external light meter for my camera.

TLDR: worried metering wont work properly on pk bodies when using the m42 adapter , and that i will need to buy an external one. Will i need to buy an external meter or what? If it helps the camera bodies i own that are pk are a ricoh kr5 and a pentax p30.