Setting permissions

Hello,

I am having some troubles configuring permissions.

I am using as DataSource a SQL Server 2014 in an AD environment. So I did the following steps:
- Added another user from AD (Database user was created successfully)
- Added a security group and a role

Now if I try to apply a permission I open an entry and try to set permissions:
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What do I have to do to set permissions? (I tried to get information using help but wasn't able to find anything.)

Thank you very much for your answer!