If you are only replacing the seals there is no need to strip the cartridge at all. With the fork top screwed in this means the spring is under tension and is pushing the bottom of the cartridge into the bottom of the fork leg giving it some resistance to turning when you remove the allen screw inside the axle point....remove this screw with an air ratchet (windy gun). It needs that sudden input of torque the windy gun gives, otherwise it will spin with the cartridge at hand tool speed.
Unscrew the fork top and the whole cartridge will come with it...separate inner outer tubes...renew seals.
Before assembling pump out the cartridge and then replace oil by volume.
Oh and don't tighten the screw with the windy gun...just do it by hand.