Stars Do Not Appear

Can someone give me a step by step solution to fix this problem. The stars do not show up on my current reviews and also do not show up when someone is trying to write a review. Since they cannot see the stars they are prevented from submitting their review. Please help!

My website is https://www.LowcountryValet.com/Reviews

I have uploaded the newstars.png file to my media library but cannot figure out how to add it correctly to the css file so that it appears.

Thank you in advance!

https://www.ads-software.com/extend/plugins/wp-customer-reviews/