If you've been trying to start it/run it and the head wasn't torqued down correctly obviously the oil+water have passed through the seal (gasket)
and now know amount of torqueing it down will cure it.
The fact that you say steam is coming out of the oil filler means that water
is comming out of where there should only be oil in therefore
the head gasket is U.S. Also the fact that you've run it like this means that
before putting it back together again the head should be skimmed as it's
almost certainly warped by now.