If you are using other apps apart from recommend apps, Please follow below steps to add review code.

Step 1:

Click on Actions button either on active theme or unpublished theme –> Edit Code

Step 2:

Click on Snippets Folder –> Locate “ratings.liquid” file. Add app ratings code ( Display stars) in this file. Check below screenshot for location.

Step 3:

Locate “reviews.liquid” file. Add app reviews code in this file. check below screenshot for location.