Great first post, and welcome to the board. I'll throw in my opinions of what you want to get down before you go to a class/ course, and what is a general good area to start.
First and foremost, remember your firearms safety. It sounds redundant, but you can't be safe enough. No instructor or fellow shoot ever wants to see a weapon pointed in their direction. You also want to remember that while working on your weapon or doing dry drills, all ammo stays in another room.
Next, you need to be familiar with how to field strip your weapon. I don't mean take it apart once or twice, I mean take it apart 10 times in a row while sitting down and watching a good movie (or the Military/ History channel). Take it apart enough so that you are very quick, very familiar, and very comfortable with doing it.
When you take you weapon apart/ field strip it, you want to disassemble the bolt carrier group every time. Too many people skip this, and it’s an important part of cleaning the weapon.
After you have cleaned it up, go ahead and lube it with whatever lube you have decided on using. If you haven't figured out which one you want, CLP/ Breakfree does a decent job of cleaning and lubricating, so its a good starting point. There are plenty of other products, but this one works well enough. Eventually you may switch to something else, but its a good start.
Then you need to start with the basics of operating your weapon. The military manuals are a GREAT source of information for this.
The most important thing you can do is know how to properly CLEAR the weapon. This would mean removing the magazine, locking the bolt to the rear, and doing a visual and physical check of the chamber and magazine well to ensure no ammo or magazine is present. Again, this is a matter of safety.
Next up would be properly loading the weapon. This step makes it worth buying dummy rounds at a firearm store. The bright orange plastic ones are usually fine, and they can't be confused with real ammo. Loading a magazine, inserting the magazine, and chambering a round are basic steps that even advanced shooters need to go over. Loading and Reloading are a fundamental part of shooting, and you can never be too smooth with your reloads (no matter how good you think you are, you could be smoother and faster).
Reloads both from an open and closed bolt would be next on my list.
Finally, I would say immediate action drills are a basic part of a weapon, so this should be included as well. You need to know how to clear your weapon if you pull the trigger, and you get a click instead of a bang. Safety is key to this again. In the real world, you can't shoot your team mate while fumbling with a weapon, and no one wants to look down your barrel as a shooter flops around with his carbine trying to clear it out on the firing line either.
There are a few other instructors on this board, and I'm sure that their versions would be a little different, but the basics always remain pretty much the same. Safety, maintenance of the weapon and basic operation are always needed to build a solid shooting foundation.
Feel free to fire away with any questions.