"I would describe this part as a valve seat not a gasket. work with the power disconnected and a cold unit. to remove valve stem pop out decal from steam wand knob, undo screw holding knob in place, remove knob (usually a wiggle job to do so). undo valve body panel mount nut. turn the valve stem to unscrew it all the way - it should slide out after a few turns. then simply remove or scrape out old rubber seal. and press in new with fingers. reassemble. could take the opportunity to apply a (very ) little food grade high temp grease to the large thread portion of the valve stem. back to the next latte"
