A little lube and two wrenches will help. Put one wrench on the die body ( it has flats for this ) and the other wrench on the top nut holding the rod , and tighten that rascal until it no longer slips.
In theory carbide dies don 't need lube....in practice , it helps big time.
Dissolve Lee case lube in alcohol , put in spray bottle and spritz cases , roll around , let dry and size.
Don't forget to adjust dies for 357's longer case.
Gary