From your 'My Hub' page (please see below)
On the left hand side of your account, you will see the side menu in which you can select 'Packages'.
Once your Stripe account has been created you can simply click the 'Create Package' button at the bottom of your screen
Where you can then assign workouts, nutrition plans etc under the 'Assignments' tab from the 4 options at the top of your page
and all details to your package including pricing from the 'Details' and 'Pricing' tabs.