Lots of security cameras but no DVR, what one do i get?
The older security camera systems use "traditional" video feeds, typically using RCA type connectors. That's likely the red connection on your camera. The yellow connector may be audio.

You should also have a barrel type connection for power.

The termination at the DVR end should involve connecting the RCA to the DVR and the barrel end to a power source. I managed to contact the new owner of my old DVR and he has confirmed that the power supply is a 12 volt DC 2 ampere unit. In this case, two cameras were powered by one power supply, through a splitter provided with the equipment.

This is consistent with other camera gear I've had in the past, requiring 1 ampere current at 12 volts DC.

You can test your cameras, one at a time, if you have an old VCR. Apply power to the barrel lead, connect the RCA to the VCR input and select appropriate settings on the VCR, connected to a television or monitor.

If you don't have three independent wires in a cable running from each camera, the above does not apply. Newer systems use POE, power over ethernet and require an injector at the DVR end and also require that the camera have the ability to accept such an input. It does not appear that your connectors qualify for this concern.