Barn Find: 1978 MGB Need Help with Electrical System

I recently got a 1978 MGB that was sitting for 20 years. I am currently working on the electrical system and am having some trouble. I replaced the battery and the ground cable and I made sure I had a good clean connection to the body. When I turned the key I only the brake light turned on. The clock didn't move, the headlights wouldn't turn on, and no other lights of any kind would turn on. I checked the connection to the starter with a meter and it is fine, and I also checked the ignition and it is fine too. But I can't figure out why I'm not getting any power. Any advice will help. Thanks.