[xwiki-users] Giving rights to LDAP(Active Directory) user on a specific space ?

I am able to login with my windows(active directory credentials) but issue is ldap user does not have any rights on xwiki space. My question is : Is there a way i can give some rights(say view rights) on specific space(say Welcome Space) to all my ldap(active directory) users. I created the welcome space and navigated to administer Space, then to rights, but do not see any way to give rights to all my active directory user.