Author's Last Name, First Initial.; Title of Lab Manual; Publisher: Place of Publication, Year; pp pages.
Costigane, B. CHEM16682Applied Chemistry 1 Laboratory Manual; Sheridan College: Brampton, ON, 2013; pp 11-17.
Your professor may have different citing expectations than library staff. Always check at the beginning of term and before starting assignments that the citing rules you are using are appropriate for your class.