In LimeWire, you need to go into the preferences/settings to add songs, if I remember correctly. I don't have it more correct,because I havn't been using LimeWire for a long time.
Besides: You stumbled into the Phex Forum with your question, which also is a Gnutella p2p Program, but isn't LimeWire.
Maybe that had a reason, and you should
give Phex a try...
Have a nice day