The sheet index near the front lists every sheet by number and title. The letter in the sheet number shows the discipline, such as A for architectural and E for electrical.
Example: a gym equipment estimator needs the architectural floor plans and the gym interior elevations. The reflected ceiling plan and the roof framing plan matter too.
Do not stop at the sheets with your trade's name on them. Other disciplines show items that affect your work, such as ducts near a backstop. Check the index against the files you received, and ask for any missing sheet.