please somebody help me out.How can I create users in datahub in order to set policies

I assume you're just trying out datahub and not using oidc to login.. there is a local file you can modify to add users, in that case. https://datahubproject.io/docs/how/auth/jaas/#modify-userprops-file-directly-local-testing

Thank you for your help. Also, do you have any idea how I can assign policies in datahub for the users that I have made.