Chemical Services are set up much in the same way as any other Services with one key exception of checking the Track Chemicals checkbox:
You must check this box for a Service to appearing in Chemical Tracking reports and this includes the Chemical Tracking Wizard on the Dispatch Board. When checked, this box will add a new tab to the overlay labeled "Products & Mixes":
Click Add Product/Mix to add a new item to the tab. The selection list will show you all active Chemical Products and any Mixes you have set up. Additionally, you can add a start and end date for each Product or Mix. This is in case you use the same Service year-round but the products used vary by season.