2007 Dodge Ram 1500 5.7L Truck won't start

When I turn the key to start my truck NOTHING
happens absolutely nothing it doesn't click the
lights don't come on the radio doesn't come on it's
like the battery is dead but it's not. It's brand new
and I have already gotten a load test done i also
put new terminals on because the old ones were
corroded very bad and one had a crack I also
checked the ground wires to make sure they
weren't corroded or loose. I just changed the
alternator a few days ago and when I hooked the
battery back up I turned the key the lights came on
but the truck didn't turn over or click when I went to
try again the lights didn't come on and it was like it
was absolutely dead again. I have no idea what I
should do next it's getting quite frustrating and I
don't want to keep dumping money for new parts if
it isn't what's causing the issue.