Look at some utube videos to learn how to use a multimeter. Once you’ve done that, read the voltage at the bottom of the socket - one lead on the ear and the other on the body. You should read around 7 volts ac.

If you have the voltage on the bottom, you should have it in the socket. One probe on the spring in the center, the other on the side. Don’t let the leads touch each other. If they do, expect a blown fuse.

If you have voltage inside the socket, the bulb should light.