Did you see the CB posts in the back or did those wires come from the plug-in harness? I ended up using twist caps (thinks that's what they're called) and twisting together the wires from the CB and the wires from the harness. No sense in me using electrical tape on those connections because I knew I wouldn't be in that truck very long.
If you saw the red and black posts, you can probably run the wires from your CB straight to those posts. If there is no power on those posts, check your fuse panel under the left side of dash, below the key. When I got in that temp truck, the previous driver had wired his to the harness and when he got out of it, he left the bare wires exposed and evidently they ended up making contact with each other because the fuse was blown. I replaced that fuse and had power to both sources (harness and posts).