How do I put the 4 wheel drive into gear on a 2500 hd silveraldo automatic

If its got the lever on the floor. put in drive, let the truck come to about 5mph and let it roll and pull lever to 4 wheel HIgh/never use low unless you get stuck (AND DON'T use 4wd ON DRY PAVEMENT,(TRY FOR A SECOND AND TRY TO TURN GOING SLOW AND YOU'LL SEE WHY,IT WILL RUIN YOUR TRUCK!)Don't keep your truck in 4wd unless you have to (FULL SNOW COVERED ROADS).If your truck is older, and your gonna be in 4 wheel drive for a extended time lock the hubs (if IT HAS THEM ,NEWER ONES WON'T)I had a 1994 silverado chyenne 2500 nice truck,wrapped it around a tree a week after I finished putting 7G's into it ,I loved that truck :'(