How does stop down metering work on Nikon F3?

I recently purchased a Nikon F3 and had a 50mm 1.4 nokton non AI lens, it mounts but is it going to work properly? How does stop down metering work on the Nikon F3? Please be as detailed as possible, thanks!

Fda

For under $25 or so, you can have the lens converted to AI.

Or, return the lens to the seller and visit KEH.com and buy a good 50 mm lens which is AI

Set aperture size using the aperture ring of the lens and the shutter speed then press the shutter release button halfway to get a lightmeter reading. Adjust aperture or shutter speed accordingly again if needed then take the shot.