1996 Dodge Ram 1500 - No Start/Blew Fuse

I left key on battery went dead then tried to jump truck with battery charger wouldnt start took cables off and charged battery turns over good but wont fire also I changed a 20 amp fuse that was by itself was blown any ideas

What was the 20 amp fuse to?

I suggest you check for spark to the plugs next. If that is good then spray a small amount of starter fluid into the intake to see if that shows signs of engine life.