You can start the association of clicker = good very quickly and easily. Get a small bag of treats, a good rule of thumb is the 3 S's - small, smelly, slimy, you may be giving them quite a few so you don't want them to choke on alot of dry stuff. First "charge" the clicker. Get your pup next to you, put the treats on a table or somewhere close by and just click then treat, repeat 10-20 times. You are building an association that the click=treat=good. Make sure though that you click and then treat, don't even motion for the food till after the click, and the click is auditory so you don't need to point it at the dog, it's not a remote and he's not a TV... hahaha. You can "charge" the clicker before training sessions for a few days or a week and he'll know pretty quickly what it is for. One of the best exercises to do, and we learned it frist week of training and every week it is still emphasized is rewarding attention. You want to be able to get that dogs attention anytime, if you are in a park and he's off leash, if you are walking and he goes to run in the street, you want to be able to have his attention always. So all you do is keep a couple of treats handy (with our pup we actually just use kibble for this since he is so food motivated I could probably use dirt... haha) and whenever the pup looks at you click, then treat. If you are watching TV, doing chores, out for a walk, if he looks click, then treat. You will be amazed at how well this works, especially for a breed that can be stubborn at times. I won't lie, Cassius is no saint and he can have selective hearing when it suits him still but this helped alot. And then it is all about clicking for a desired action like Heather said. Two important things to remember though, the timing of the click needs to be right as they are doing the action, and any time you click you treat at first, even if you click by accident.
Check out
Clicker Training
There is a basic book she sells that is really good, we use it in addition to class and it is nottoo expensive.
It has some amazing things that clicker or marker based training has accomplished.. horses, mules, cats, rabbits, pandas... not to mention there's a great looking boxer on the homepage. Marker training is how the Navy trained dolphins.