Just to expand a bit, after 1st level, you have some choices.
You can continue to give out max hit points, which we did for a while during out playtesting, but ultimately thought that was a little too much. We scaled it back to average per Hit Die, rounded up (7 for 1d12, 6 for 1d10, etc).
We all preferred a set amount of hit points as opposed to rolling as well but that's more of a personal preference.