| Eric,
I can't give any info specific to the 93 Lumina, but I can give you some pointers that will help you get it apart. When I was installing, I would run into cars I had never worked on before, so figuring out how to take a dash apart without breaking it was essential. First, before you even touch a tool, carefully look the situation over, and get a feel for how it comes apart. It seems you have already done this step. Most manufacturers (I say most, because GM has been notoriously the exception here, but they are getting better) will make it easy to get a specific components in the dashboard, such as instruments, heater controls, and radios without having to completely dismantle the dash. Look at it from all angles, up and down, and try to find hidden fasteners, usually under a small snap out panel, or a plastic plug. Sometimes they are hidden behind a pull out switch, or even behind the ash tray.
Now, carefully remove all the fastners you find, and begin to carefully remove the panel. Some panel clips require a decent amount of force to free, but if you feel you need to pull too hard, stop, and look for a fastener you might have missed. If you have to really force something, you are probably doing something wrong. Just take your time, be extra careful, and think it out. You should be fine.
Tony | 
