Peer-to-peer network allows users to share files with other users. All users connect to the special computer called hub that routes search requests/results and facilitates clients to connect to each other. All file transfers are being made directly between clients, not through the hub.
First of all you need DC++ client software. Then you can connect to the hub, search for the files you need and put them into download queue. You may also view all the files single user shared with everyone.