Its time to change the hydraulic fluid in my 1520. I see what looks like two separate drain plugs underneath. I do know where the engine oil plug is. Do I pull both plugs to drain? Also, can only find the dipstick (between my feet) but no signs of a fill point. Do I have to put like 23 quarts of hydraulic fluid into this tiny dipstick access point?

Thanks in advance to anyone with knowledge!!