Lighting, Light Fixtures, Ceiling and Exhaust Fans - Replacing ceiling light fixture

I am in the process of replacing a ceiling light fixture. I'm definitely NOT an electrician. I understand connecting black to black and white to white, but there are four ground wires that are crimped together. I'm not sure what to do here. Should I disconnect the crimp, attach one of the grounds to the ground screw on the bracket, and then onto the ground of the new fixture? Then should I recrimp the other three ground wires? How do I know which ground wire to use?

I guess I should also say that there are three black wires coming together to form one, three white wires coming together to form one, and then several others that seem to be hot that are taped together and had not been connected to anything. Would I just be better off having an electrician look at this?

Thanks!

Any ground is as good as another to connect to. I would try to connect to one that may have been left as a long tail, but they all need to be mechanically joined together.

If you need to remove the crimp just rejoin all of them and the fixture lead with a wire nut.

Make your connections to the new fixture to the same wires as the old fixture. Do not bother with any wires not connected to the old fixture.

The crimp requires a special crimping tool. You don't have one, and a pair of pliers will not substitute. So, as pcboss says, use a wire nut to reconnect them.