To add more than one Product to your Sales Page, the first step is to click the "Gear" icon shown below and add the additional Product(s) to the Product Manager (Product 1, Product 2):
Next, click the Sales Page object on the canvas to view the Object Settings. Then click the blue "Add Product" button shown below:
You second product will be added to the Sales Page as shown here....
If you have another Product, you can add that next. Also, you can modify the Sales Split % based on your Product sales projections.