1985 New Yorker, pleeez help

please help me out if you can, i jus got my first car, an 85' New Yorker. I have only had it for about a week and the lights are all screwed up. When i put on the head lights the rear right signal doesnt work and when i put the signals on the whole dash flashes at the same beat as the signal lights. And when i press on the brake the dash lights go out, when its released they come back on. It wouldnt be as bad if the whole damn car wasnt digital!!!! Although its all quite funny it wont be funny when the tickets start piling up. Please help me please!

Go over all your grounds. This includes removing the bulbs from their sockets and cleaning them.