Julie here from Shopify Support.
You can generally access the help documentation for an app directly within the app itself, or under the Support section on their app listing in the Shopify App Store.
It looks like Affilio has a Help Center, but it's currently under maintenance. In the meantime, the developers are scheduling one-on-one calls with merchants, which you can book directly through their Help Center.
Let me know if you have any further questions!