Well I would take the carb off the back of the engine.  Remove the back plate and check the main bearing for rust.  I would then put oil into the cavity and make sure it moves all around inside the cavity.  I would invert the engine so that the intake manifold with the carb off is facing upwards.  I would shoot some oil down that manifold, turning over the engine will introduce the oil to the top of the enginel (piston area),  I would take the valve cover off the top, check the tappet clearances and oil that area up too.  I would dribble a little oil down both push rods so that some oil gets to the top of the cam area, it will seep around the cam followers and get into the cam shaft area.

Then I would reinstall the back plate and carb and with no glow plug installed turn the engine over 15 or 20 times.  That will get the lub every where.

Then I would attempt to start the engine with a new glow plug installed. That should get it running The actual running will expel all the extra oil.

BTW, if the carb is not open with testing for compression you may get low compression.  So make sure the carb is open when testing for compression.

Otherwise, get someone who knows the engine to disassemble it, clean it up and install new bearings.