Been there very recently with my 98. Give me a little time and I should be able to point you to a step-by-step description on scoobymods - although that one describes a 99 (I think) so the cup holder is not quite the same.
I did this job about two weeks ago, but made one mistake - the procedure cites a certain Radio Shack bulb. I went to a store near me, and the closest thing they had was a 2.5V mini flashlight bulb. They fit, but burned out instantly. Apparently those lights get 9V.
Basically, it's like this: Pull out the cup holder and remove the two screws that hold it in. Pull out the ashtray and remove the two small screws, which face down. You might have trouble getting a tool on those; I used a small right-angle screwdriver.
Now you can pull off the bezel that goes around the radio and vent controls. You need to pull off the wires to the lighter. You can also pull out the bezel with the central vents, this is held in with clips and you can carefully pop it out. Pull the plug to the emergency flasher switch.
(I took the opportunity to take all these parts inside and wash them; mine were filthy with my other half's spilled Diet Pepsi. In fact, I was able to restore the cup holder to its original condition once I washed the gunk out of it.)
Now, the vent control panel is held in with four screws. Don't let them drop! Then you have to disconnect three plugs, each has a top center tab you have to press in to release. Finally, there's the heater control cable - it's held on with two C-clips. I could not get them to open, even with the special tool. So I popped the pivot point instead, and pulled the vent controls with the lever still in the dash. You'll have to take the plastic end knob off the lever, no big deal. The clip that holds the cable sheath popped off easily.
On the back bottom of the control set, there's a piece you can almost remove ... but a plug won't let you. You need to lift off a clip that holds the plug in place.
Finally, you're looking at the printed circuit board on the back of the controls. The three bulbs are in small brown sockets that twist out easily. The bulbs themselves are the size and shape of a grain of rice.
If you get the new Subaru bulbs, they come with these sockets. The Radio Shack bulbs I got just had bare wires, but I could thread them in like mini Christmas light bulbs - except for the one behind the fan control, which has a socket too long for the bulb wires.
BTW there is another socket and bulb in the back of the emergency flasher switch.
(I am waiting for my local Auto Zone store to re-stock their bulbs; I don't know what their closest match is. The ones they showed me were sealed glass bulbs like smaller versions of driving light bulbs, without the wires.)
"Installation is the reverse order of removal."