Exact method is year dependant.... Basically, you remove the bezel surrounding the cluster, remove the cluster, remove the bulbs and replace them. Reassemble. It is fairly easy to do, just take a bit of time.
If I remember right, it's been a while since I had mine apart.
Depending on how many you have burnt out you probably have a few spares already in the instrument cluster, like if you have a part-time transfer case the "full time" bulb is a spare, I think there's an "ABS" light too that probably isn't needed. Bulbs that are always on I'd consider spares too, so "check engine", "airbag", "low washer fluid", "check gauges", "parking brake", etc.