This is a hypothetical question as I'm not actually taking part in tournaments but the question is I think worth posing.
I was non-chalantly playing this as black against a chess.com bot:
[StartPly "11"]
[FEN ""]
1. d4 a6 2. d5 e5 3. e4 d6 4. Nc3 f5 5. exf5 Bxf5 6. Nh3
At this point I say to myself, what a novel opening! I have no idea what to do.
I can come up with many themes and ideas disjointedly: white might use the e6 square as an outpost later, pawn to f4 is also possible for white - either chipping away at black's center or provoking black to push e4, which would take resources to defend but would also stop Bd3, which is good for black because white's bishop isn't ideal on c4 or e2... et cetera.
I have a hard time ranking these or knowing how to connect these ideas, let alone precisely calculating what lines are there given the non-forcing nature of them.
I am aware that as opposed to a computer, a human in a timed game can't do a perfect job. But can you tell me how a good player would go about it, using my position as an example? I haven't turned on the engine because I don't want to take the fun away just yet.