So, all of your standard tutorials don’t have this information in it as there were some recent changes to the way that the Ark: Survival Evolved dedicated server works as of a recent update to Windows 10 from 1809 to 1903 as well as the latest update to the game itself. The “enable cross-platform play” check box is missing.
You may still want to setup your dedicated server. First of all make sure that your router supports UPnP (Most do automatically), Determine what your host (PC) network type it is set as “private” or “public”. Enable Windows Firewall for that profile (This is a requirement or it will not work).
Before you start the game, on the PC hosting the dedicated server go to Settings -> Gaming -> Xbox Networking. Your NAT type should be set to “open”. If not, click on “Fix It”. You may need to restart your computer for the settings to take effect.
Once the computer has restarted launch the game and setup your dedicated server. Send invites through the admin panel to invite friends. A dedicated servers uses a dedicated Microsoft Live account. If you as the admin would like to play you will need to configure another Microsoft account to host the game as such that you may join the server instance as yourself.
Hope this saves a few people from some headaches configuring their dedicated Ark servers.