Hi @rmendoza,
Welcome to the Auth0 Community!
Usually, you can accomplish this by using a Post Login Action flow. In the script, you can use the Management API to assign roles to your users.
Please see this related knowledge solution regarding this:
Now, you will want to make sure that you have these Salesforce roles created in your list of Roles before assigning them to users.
Lastly, if you were to use a refresh token to get a new access token, all of your action scripts will rerun and trigger again.
Keep me posted on how this goes for you.
Cheers,
Rueben