02 silverado amp install question

Im installing a 5 channel amp in my 02 siverado 2500 hd w/duramax. How can I connect the power feed from the electrical distribution box to the amp? I think this would make a clean install but Im not sure if its a safe place for the connection. Any help would be greatly appreciated

Run the positive (+) straight from the battery and connect the negative(-) to the chassis....Thats how my amps are connected