Julie here from Shopify Support.
It's great to hear that you're wanting to show product reviews on your online store. This is a great way for customers to learn more about your products and can definitely build trust from buyers.
If you're having troubles with the Areview app, I suggest reviewing the developers' help documentation. The Areview developers actually have an FAQ that you can access right here. There, you'll get answers to frequently asked questions about how to use this app and how to integrate it with your online store. You'll even find a section on how to import reviews, which should help guide you along!
If you're still having troubles fetching your reviews, then it's best that you reach out to the app developers directly. When it comes to getting help with third-party apps, the developers themselves are the best to assist since they know their app inside and out. You can typically find contact information for app developers directly within the app itself, or under the Support section of their app page in the Shopify App Store.
I hope this helps guide you in the right direction!