Click "Play" on the session, and take a listen. You'll notice that, with the exception of the overheads, everything is on the same "plane" in the stereo image. A stereo image has two channels - left and right - to simulate both ears on the human head. Within that stereo image, you can move items from left, to right, to back to the center. Why do this?
First, it gives you something very psychologically important. The listener hears with two ears in nature, and when listening to something in stereo versus mono, it brings the subject to life. The listener is more engaged, and feels more "connected" with the recording. Second, it allows you to separate items of different timbre or tone, and allow the recording to come together with items that would otherwise sound "cluttered".
Let's look at the drum kit as if you were facing it. Keep in mind that my tips here are for a right-handed drummer; if your drummer is left-handed, just do the opposite of what I'm recommending, if the high-hat is on the right instead of left.
The kick and snare should always stay centered. They both form a very important aspect of the song, and form a very strong backbone on which the song sits. You can, of course, experiment -- many recordings have the kick and snare panned in non-traditional ways -- but for most rock recordings, you'll keep them centered.
Next, look at the toms. You have four toms on this recording -- high, mid, low, and floor tom -- and those should be panned as you'd be seeing them, with the high tom leaning right, mid in the center, low leaning to the left, and the floor panned hard left.
Next, let's look at the high-hat and overheads. Naturally, the overheads need to be panned hard left and right, since they're recorded in stereo. The high-hat will be panned hard right.
Now, let's go on to gating and compressing.


