Merge columns and manipulate data in three small Excel files

Hello, I need three, separate, small Excel files worked on. They contain transactions that need to be in a specific format. The final fields needed are, in this order: Description of Property, Date Acquired, Date Sold, Sales Price, Cost Basis, Gain or (Loss). Gain or (Loss) must be a calculated field derived from the Sales Price and Cost Basis. The Quantity needs to be included into the Description of Property column. Sales Price and Cost Basis must equal the Gain or (Loss). After this is completed, all other columns can be deleted. Please advise. This needs to be done as soon as possible. Thank you. Jerry Johnson