Pivot Column turns values from one column into new column names. A list of room reservations can become one row per site with Morning and Afternoon columns. Select the column whose values should become headers, then choose the column that supplies the cell values.
Every remaining column becomes part of the row identity. Remove a transaction identifier first when the required result is a summary by site. Otherwise each transaction stays on its own row and the pivot looks sparse.
The aggregation setting answers a separate question: what should happen when several records land at the same intersection? Sum adds quantities, Count counts records, and Maximum keeps the highest reading. Don't aggregate is useful for text lookups when each intersection has one value. It doesn't silently select the first duplicate. Check uniqueness before choosing it, and preserve null for combinations that have no source record.