A two-way lookup finds a row and a column before returning their intersection. In the Capacity sheet, the team names run down column A and months run across row 1. A hard-coded column number works only until somebody inserts another month.
Use MATCH twice inside INDEX: the first MATCH finds the team, the second finds the month. Both searches use exact match, so an absent label produces #N/A instead of a neighboring result. You can also nest XLOOKUP. The inner lookup returns a whole row, and the outer lookup selects the month from that row. Keep the headers outside the numeric body and lock the source ranges if you'll copy the formula.