I have installed a new SCCM 2019 (1906) server as a CAS and have a separate DC server. We planning on setting up the CAS server role in our main site then create two other secondary sites for remote offices. When I go to discovery methods only the Forest Discovery is listed since I only have a CAS server. Do I need to setup another server in our main site to add the other discovery methods or is there a role I could add to the cas server which is at our main site?