Hello friend, in the DW multiplayer menu you can only connect via IP. This means you need to have somebody you already know host a game. He must then give you his IP address for you to connect to him. You can not randomly find games from the DW multiplayer menu.
You can download something called Hyperlobby however. This will allow you to find random games (It works for many different games and is the primary way to find online games in IL2, Lock on, and more.)
The bad news is, I have never seen any DW players in Hyperlobby. Maybe I just have not checked at the right times. As far as I know, it is your best bet.
Also, post up in the multiplayer match up forums for DW. That should be a good way to find someone else to play with.
If you would like to try Hypperlobby, you can download it here:
www.hyperfighter.sk