tail light question

[Rockken]

Guys, I want to add tail lights to my 88 and need to know a few things. There are two bulbs in each tail light, I need to know if one of the bulbs is used for the tail light and the other is for the brake/blinker, or if there is a different configuration for tail light, brake and turn signal. I also need to know which side of the dash the wiring for the tail lights is on. All the original wiring to the back has been stripped out.

Thanks
Ken