It's all per manual.....just drain (& measure how much comes out in case you don't disassemble the damper units) the drain bolt & then undo the 'underneath big bolt' & withdraw the fork lower....seal is a circlip then screwdriver/suitable puller. Just drift new seal in & replace circlip (it's not pressurised, just holds the ATF in the fork). Carefully refit fork leg making sure the spring end cap groove aligns with lower cap thing in lower leg (some are plastic, some metal) refit lower 'underneath bolt'...refill from top with same amount you took out (or refill with recommended if you stripped it all down). Assuming you have manual, it's straightforward & only thing I remember is that 'forks back tightenend in yolks' is the best way to hold stanctions/fork (incl wheel sometimes) to undo/retorque lower bolt and top bolt.