There may be some products that can only be purchased if another product has been purchased. For example, you may offer jerseys to participants that have registered as under 18 and a different jersey for those over 18. These are called Conditional Products.
NOTE: you must create the main product first.
Select Products & Forms from the top menu, then select the Products tab.
If your product does not yet exist, click Add New Product and complete the wizard.
If your product exists, click on the name to open it and go to the Display Rules tab.
When you get to the Conditional Product section, click Create Dependency.
From the line that opens, click the magnifying glass icon to select the product that this one depends on.
If the main product must be paid before purchasing the dependent product, tick the box.
When you are done, click Save.