To include a product with a package, head to Revenue Builders > Products.

You will see a list of all of your products here.

On the packaged column, click on the text in the column. It could say none, some, or all, depending on which packages you select to include in your product. 

You should see this screen:

From here, select which packages you would like to include your product. You can also click the 'Make available for all newly-created packages' box to add your product to any packages you create.

Click 'Update Product' to save your changes. 

You now have successfully added a product to your package!