Deadman switch is also called the tether on throttle/shift pod or on dash someplace with curly cord and snap to attach to yourself. It disables ignition.
Don't worry about oil or fuel. Crank over with out plugs in engine for 30 seconds before taking first cylinder's reading, screw gage hose in hand tight and then crank over until gage needle stops climbing. Then stop cranking. Proceed to next cylinder.
check manual for desired pressure and acceptable range. usually gages are not that accurate but each cylinder should be within 15 psi of average of other readings. This test shows if there is an excessively scored cylinder wall, broken ring or burned piston.