how to change a head gasket on a 2008 dodge ram 5.7 hemi

The cylinder heads needs to be removed, the gaskets removed, the cylinder head checked for straightness at a machine shop, the gasket mating surface needs to be cleaned of ALL debris, the replacement gaskets need to be installed, the cylinder heads need to be torqued to the proper specs and everything needs to be reassembled. I hope disconnecting the battery was the first thing you did. This is not a job for the average do it yourselfer and if done incorrectly will need to be soon done again. I would NOT mill the heads if they are straight and flat.