Start with the five reads this piece sets out: contribution after each channel takes its cut, prime cost as one number, rent against realistic revenue, the gap between a busy month and a banked month, and what the operation earns when the founder is not in the building. Each read links to its own deep-dive on this site, and the Diagnostic Command Report assembles the figures you type into one structured read.
From A Busy Restaurant Can Still Be a Bad Business — the full reading, with the method behind this answer.