One more question, how can i set the access level for the category/group?

You adjust the Access parameter while editing your category/group as needed.

now on the front end when i'm logged in with normal user i see all admin features, i can even delete the main category and group

You either have your CB moderator permissions set wrong (as in every user is being considered a CB moderator), you're not logged in as a normal user (e.g. logged in as a CB moderator), or you're logged in as the owner of the category/group.

First check within CB > Configuration > Moderation and ensure "Moderators View Access Level" is set correctly (I recommend "Special"). Next edit your user within CB > User Management and ensure they've the appropriate usergroups for your testing.