Cut the nozzle tip of the sealant tube at a 45-degree angle
Puncture the inner seal of the tube with a long nail or the built-in puncture tool on the gun
Pull back the plunger rod on the sealant gun fully
Press the release tab if the gun has one
Insert the sealant tube into the gun with the nozzle facing forward
Push the plunger rod forward until it contacts the back of the tube
Squeeze the trigger slightly to engage the plunger
Check that the tube is seated securely and ready to dispense