What to do with this old Coax. TV?

what do you want to connect it to?

If you are going on about Digital switch over all you have to do is connect the Digital box to it most come with an RF or scart port . If its a games console you gan buy an adaptor to convert it to scart unless you have the Yellow, Red, White ports Audio and Video < just plug into there.

You can hook it to a VCR, or DVD player and watch movies. There is a probably a box full of them near where you found the TV.
Most players have an RF output. Set the TV to match the VCR’s output channel usually either 2 or 3 if you are in the US.