Highly recommend a n00b take my advise and DO NOT split the case. If there's no metal in the pan or the filter just leave it alone. Change rings and do up all the gaskets - being a n00b you will probably make mistakes even going that far unless you read for a solid couple months on the subject and buy the correct tools.
I have many old posts on the subject and why this is the case. Search is your friend.
And in general Subaru engines are not economically viable to rebuild in the first place - ReSEAL yes. Rebuild no.
GD