Student work in Perusall is graded automatically, but instructors always have full control and can override the comment scores provided by Perusall.
Within the assignment: Open up the assignment and then you can see all of the highlights and conversations as students see them. To see the individual comment score assigned to each comment as you are reading, click the filter dropdown menu (which says Options by default), then select Show comment scores. You will see a score for each comment beneath each comment bubble, and can change a score from Perusall's automatically-generated score by clicking on the Quality score and selecting a new score from the dropdown.
In a spreadsheet: If you would rather review the comments in spreadsheet format: go to your course dashboard, select Assignments at the top, click on an assignment, then click All comments. Individual comment scores will show for each comment in this view, and you can change a score from Perusall's automatically-generated score by clicking on the score and selecting a new score from the dropdown.
Grade Assignment: If you want to see the grade breakdown (including each scoring component) for each individual student, either click Grade Assignment from the desired assignment details or click on a score within the gradebook. Within this window, you can override the automatically-generated score by typing a new number into the top left text box. You can also see each individual comment made by the student by clicking on comments submitted.