ASSEMBLY: First you have to attach the high pressure grease hose to the head of the gun, making sure you use the supplied copper gasket before tightening down. Then, you have to attach your inlet coupler to the bottom of the handle, making sure that you use teflon plumbers tape on the coupler threads.INSTALLING GREASE CARTRIDGES: First, remove the pump head from the grease cylinder. Second, pull the grease loader (Also called follower) all the way back and then lock it into place. The side which has the simple pull off cap, that end goes into the grease cylinder. Then you pull off the sardine like lid, and then screw down the pump head onto the grease cylinder. Then you release the grease loader.PRIMING: Every time you install a new grease cartridge, you have to prime the gun. The quick way to prime, is to operate the gun slowly, until grease flows out of the coupler. If that does not work, you may have air pockets in the system. The manual recommends that you open the filler valve on the pump head by two turns out, holding the gun with the discharge hose pointing up. Then you close the filler valve once the air has been removed.OPERATING: To operate, attach the coupler at the end of the high pressure hose, to a zerk fitting. As you depress the trigger, air enters the chamber, which pushes the piston with the plunger. The grease that is under pressure from the plunger, opens the check valve and delivers one shot of lubricant. The more you depress the trigger, the faster this process operates, thus increasing grease flow. The gun is designed to have a full speed limit, as to limit damage to bearing seals and dust boots.EXPERIENCE: I think this gun weighs a bit much, but it has to be constructed of durable metals, in order for it to be commercial built. The body of the gun is constructed of a durable metal. The handle has a really nice rubber grip that I like, while the trigger is made of plastic. On both ends of the high pressure hose, heavy duty springs can be found. These springs are used to make sure the hose doesn't kink, I find they kind of get in the way, but I can get used to them, just have to have a good grip on the hose is all.I find its best to just let the bottom of the gun rest against the ground, this way you don't have to hold the weight for long periods of time. I like the 30" HP hose on this gun a lot more then the 17" hose on my old gun, as it allows me to get deeper into a place that has a grease zerk. Using this gun is so easy! All I have to do is press on the trigger a little bit, and grease will automatically be pumped into the grease fittings. No more hand fatigue, and no more useless time wasted, trying to fill the fitting with grease.One of the things I like that Lincoln Industrial did, is they incorporated their cover cap, into this gun as well! This is a great option, because when you are done using the gun, you can slide the cap onto the end of the coupler, keeping the grease from getting contaminated by dirt.CONCLUSION: This is the best grease gun I have ever bought! Not only is it made by a awesome brand like Lincoln Industrial, but its extremely durable. Despite a few of the negatives, I really like this gun. I can tell I am going to get a lot more use out of this gun, then my old one. This gun is not necessary for the home-owner per say, but is absolutely necessary for any small engine or automotive shop. 5 out of 5