I'm not sure from your message whether the engine is turning over or not. If it's not turning over, I would begin by using booster cables to see if the engine will turn over properly - check the manual for specifics on where to hook up the cables. The battery is under the box, where the spare should be, so is not readily accessible.
A clicking sound without the engine turning over could indicate the battery has enough current to kick in the starter solenoid, but not enough to turn the starter. I had an electrical drain problem with my Duramax pickup - turned out to be defective contacts in the ignition switch allowing some systems to continue draining. If everything is operating properly, the electrical system should shut itself down after a specific period (unless the SSR is done differently from several other GM vehicles.
If you do get it started with cables, make sure to put the battery through a full charging cycle - unless you go cross country, running it will not properly recharge the battery.
If the engine is turning over but not firing, it's getting a little more complex - possibly a sensor out of commission making your computer unhappy, or a problem with fuel delivery - unfortunately probably means a visit to your friendly GM dealer on a towhook. I would strongly recommend trying to get a deck truck, rather than risk damage from a towtruck.
A clicking sound without the engine turning over could indicate the battery has enough current to kick in the starter solenoid, but not enough to turn the starter. I had an electrical drain problem with my Duramax pickup - turned out to be defective contacts in the ignition switch allowing some systems to continue draining. If everything is operating properly, the electrical system should shut itself down after a specific period (unless the SSR is done differently from several other GM vehicles.
If you do get it started with cables, make sure to put the battery through a full charging cycle - unless you go cross country, running it will not properly recharge the battery.
If the engine is turning over but not firing, it's getting a little more complex - possibly a sensor out of commission making your computer unhappy, or a problem with fuel delivery - unfortunately probably means a visit to your friendly GM dealer on a towhook. I would strongly recommend trying to get a deck truck, rather than risk damage from a towtruck.
