How do you install deck belt on 46inch huskee lawn mower?

Remove the deck. First by pulling the pins that attach the lift brackets, and then remove the rear spring, and the 2 belt guides under the engine for the belt that drives the deck (1/4" socket). After the deck is out, release the spring that applies tention on the right idler pulley (you'll have to remove the 2 side pulley covers).