Turntable knowledge reqd. – cartridge newbie!

I just bought a new turntable second hand, and am looking to swap out the cartridge for a new one. I understand the workings of the cartridges, but I have no clue whatsoever about the fittings of cartridges since this will be my first TT with a removable one.
The pic below is of the table, and it looks like it takes a standard fitting, with the two screws. But it -also- looks like it takes a P-mount screw behind that. Or is there something else circular that I don’t know of? Could the standard mount part be an adapter?
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Answer #1
Looks like 2 screws to me..
If you have the TT then you should be able to figure anything else.
Looks like you can unscrew the cartridge holder from the arm to make it easy.
Answer #2
what’s the full make and model of the TT ?
Answer #3
Turns out it is a standard mount. Luckily a friend saw it as I took it out the box and commented on it. I’ve opted for a Shure standard mount cart, I’ll update when it arrives
Answer #4
Here’s some help to become the vinyl king !
http://www.soundfountain.com/amb/ttadjust.html
Answer #5
just un screw the little ring with a little file thing should just come off then there pretty easy to change