To Set up User-Role based discounts you will need to set it up from the rules and restrictions page, you will need to specify that you intend to apply the User Role rule.
User Role rules can be configured in two ways, they are whether the user role is equals to or not equals to the preset selection.
You can choose the user rules whether equal to or not equal to the following user roles.
Here, you need to choose the user role on which you want to exclude the usage of these pricing rules. In this example, the pricing rule will not get applied if the user role is a contributor.