HTC EVO 4G :: Doing Toast's Root? Put PC36IMG.zip File On Root Of Your Sdcard

Then I tried doing Toast's root and got confused at step 2 (the adb step).
Now, I know a LITTLE about what ADB is and that you basically only need it so you can use your computer to type/see things instead of doing it all on your phone.

(This is the thread that I'm using by the way: [TUTORIAL] How To Root The HTC EVO ~ Part-1 / - xda-developers)

1. So, so far, I downloaded SDK package, saw the "tools" folder and see the "adb" file. When I click on it, it pops up like a "command/cmd" screen and disappears. Is it supposed to happen like that? Or am I doing something wrong?

2. Also, in Toast's method, when he says to put the PC36IMG.zip file on the root of your sdcard. What does he mean by that? I'm sure it's something simple but I'd rather be sure how to "put it in the root of your sdcard". Just that mean just right in the front by all the folders?

3. Next thing the page says is: "adb push PC36IMG.zip /sdcard"
I don't know what he means by that. Am I supposed to do something here?
The steps follow this (until it's Rooted) I understand but not this.

4. Then after rooting there are some other steps he has in the original thread that say somethings about "adb shell, adb.. etc"

What do all those mean?