Well, I've been wondering this for awhile. So far I've heard for the preamp tubes you can just take them out and put in new ones and be set. But What about power tubes? Can someone explain this to me carefully? I've tried everywhere but nothing makes sence to me. Oh and what is bias?
I don't know it off the top of my head but look on youtube, there are some good tutorials there.
if you don't know how to do it, then take it to a pro and watch the first time. you could theoretically kill yourself by touching one of the parts in the amp that carries residual electricity.
I'm putting my GAS on hold
for a couple months in order to pimp my ride.

Don't judge me.
It depends how the bias works in your amp, if it's cathode bias, you just plug and play, if it's fixed bias you need to manually set the idle current for power tubes. Too high will fry them, too low and you will get crossover distortion.