Basically, turn your connection setting to either active or passive (passive is easier, but some hubs don't allow passive searches, so you should probably set to active. You'll need your IP, and the ports should be in the help files). Then you simply join a hub (View > Public Hubs). You can filter the hubs to find hubs that deal in what you want. Then use the normal search function (not Searchspy or ADL search) and get downloading.
The big thing with DC though, is you'll need to set up your share before getting out and joining hubs. DC is not a program for leechers. Almost all decent hubs will require you to have several gigabytes of appropriate material to share. If you already have your music and videos organised into folders, this is relatively simple, though somewhat time-consuming.