Right behind the shifter should be a plug and vent tube that screws out. Down on the left side of the trans housing you should have a round site glass. It has a white back ground and if the fluid is nice and clean it's very hard to see the level.
I'll warn you ahead of time, the L3000 is picky about how you check the fluid. It needs to be sitting on very level ground to get a accurate reading. Hope this helps.