Are you are talking about the readers of the blog rating a post? If so, you might want to try
1) Dashboard > Layout > (Blog Posts/Blog Posts Widget) Edit
2) Check box next to "Reactions" and change "Reactions" to "Rating".
3) Click the "Edit" button at the end of that line
4) Replace the words "funny, interesting, cool" in the box right next to where the "Edit" button was with "★, ★★, ★★★, ★★★★, ★★★★★" (without the quote marks)
5) Click somewhere else on the page to exit the box. You should now see 5 boxes with one, two, three, four, and five stars
6) Click on "Save"
Each post should now have a way to be rated (if that is what you were referring to).