Just brought a nikon 50mm lens but the thing inside it won't open?

So i can't take pictures with it
there's this thing inside it which is supposed to open
and i dno how…

when i put the lens on the slr body it says F-- and it blinks…
how do i fix it?

Added (1). Why does my camera say f-- and it keeps blinking? It won't let me take photos

Is this an older lens? I have seen people with older Nikon's have this problem. Set your F-Stop all the way open (little number) and turn your camera off and on. Not sure if that will fix it but I saw this work for someone else before.

"there's this thing inside it which is supposed to open"

That's the bit that needs a lot of clarification.

The F-- is because you didn't set the aperture ring to f22

I'm guessing the lens isn't designed for your camera mount. The blinking f-- indicates that for some reason the camera can't control the aperture opening of the lens.

Either the lens is defective, or it's not made for your camera mount. Either way, the lens isn't communicating with the camera body.

Edited to add: Check the manual for the lens. Some Nikon lenses apparently have a way to switch the aperture control from manual to automatic. If it's in manual, you'll get the flashing F.

If you read the bloody manual, you would know that you have to set your lens' aperture ring to the lowest aperture and lock it there and order for it to work.

If it's an even older manual focus only lens, then the only mode you can use it in is in "M" mode.