If you plan to use Recurring Cart mode, setting it up is easy!
Click Settings > Recurring Style and choose Recurring Cart mode.
Once you've selected this mode, any time you need to make changes you can just click on the Recurring Cart tab found in along the main app tabs.
Select how many recurring interval options you would like to offer, and the number you want to allow for each interval. You have to choose at least one interval: day, week, month, year.
Lastly, you can enter a percent off if you would like to offer a discount if they subscribe to their cart. This is not required. Don't forget to click 'Save'!