The formula in column I checks if the manager name in H is the one you selected in the TEAM sheet. If so, it adds 1 to the count of matches as you go down the list.

The Max() formula, gives the last (largest) number returned which corresponds to the number of matches...

This is used in the final formula to "error trap". I.e. if the number of boxes is more than the max, then return a blank instead of giving an error.

For each box, a count is made of previously filled boxes, to determine what "box number" we are at... if we have a match of the corresponding "box" number in the Setup sheet, then the corresponding name (SetupConsultants column) to that number (from column I)

You can use the formula Auditing tool, found in the Tools menu to step through the formulas.