How to configure access rights for issues in an organization on GitHub?

I set up an organization on GitHub and invited some members. Most members have the status member. They can create issues, but are not able to set a label or to assign the issue to another member. I figured out, where to set repository permissions: https://github.com/organizations/{MyOrganization}/settings/member_privileges. But what I need now are ticket system related permissions.

How to configure the project ticket system access per user? Additionally: How to do this per team?

Unfortunately, that's not possible yet. Many organisations have used GitHub bots to assign labels automatically, without giving users write access.

Edit: If you are okay with having you're users have write access (i.e. can pull/push/clone), then you can go to https://github.com/orgs/{org}/teams/{team}/repositories and configure access there.