Brake Lights Not Working

Hi guys! I'm new here and don't really know a whole lot about these vehicles so i'm looking for some helping minds! So, on my 1970 Plymouth Valiant with the 318, my brake lights don't work. turn signals and all other lights work just not when i push the brake. I checked the bulbs, they were okay. When i checked the fuse, it was blown. as i went to insert the new fuse, the fuse instantly blew and the vehicle wasn't on. the only way i could make that connection not hot was to unhook the battery. i need some guidance on where to even begin and all help is appreciated!