If you just got SIRIUS and want to know how to install it, you should read this article and be able to.

[edit] Steps

Run the antenna wiring up to the front of your vehicle.
Clean your windshield with an alcohol wipe.
Suction cup the mount to the windshield.
Screw the receiver to the mount.
Connect the antenna to the receiver.
Plug the big end of the power adapter into the cigarette lighter or power outlet.
Plug the other end of the power adapter into the receiver.
Turn your vehicle either on or onto accessory mode.
Press the button in the upper left-hand corner to power on your receiver.
Tune your radio to 88.1 FM.
Call Sirius at (877)-539-7474.
Press any key to continue.
Turn the channel to make sure your receiver is working correctly.
Start listening to Sirius.

[edit] Tips

If you ever feel that you cannot install Sirius, have a fiberglass roof (like on a Corvette), or have a direct connection to your radio without a receiver, seek professional help.