Need to set the pressure reg on the pump to ***psi (edit) should be 100PSI. Adjust the smaller separate brass little Valve to give the oil pump chain a slow drip, a dribble on that will launch oil every were, a drip causes no issues! Before going further it pays to make sure the sumps clean, they tend to fill up with shit, the oil suction strainers clear and most importantly the oil return line and its little filter basket are clean, any of these bad makes a serious mess of over flowed oil!
Then you adjust the oil flow to the table ways by removing the bolt - plug in the top of the table speed control lever, bellow that is a locking grub screw bellow that is the needle valve, You want just enough to keep the ways damp, no more, it then runs out and down from there to the V ways, of the cross travel. Set right its a great lubrication system and little effort. Its one of the key reasons so many J&S 540's i have encountered show nothing like the way wear despite there age of a lot of lesser grinder.
DON'T forget it does NOT lubricate all the screws, nuts and rise - fall mechanism, some J&S 540's have auto lube pumps that do some of these spots but not all, on mine there's several locations that still need the attention of a oil can - oil gun.
You need to get a manual, there's normally plenty on ebay and there pretty dang cheap, as far as i know there is no online digital copy.
PS welcome to the club, there a nice grinder, at least over here there kinda what bridgpeports are to milling as grinders go, there also pretty damn mechanically reliable. Once through typical age related teething issues, they work a treat for a long time with near zero effort.
That said, you do want to check the metastatic mounts for both the spindle motor and for the pump frame in the hydrulic sump, both age and fail in time, easy, just sods to get to replace, there plenty cheap enough and you need 7 if doing both spindle motor and pump frame.