Hello Panda,
Well, there are two answers to that question:
If you are hooking up two computers to create a network for your rescued files,firstly you would need a second computer along with a cable, the correct cable (called an RJ-45) has an end that looks like an over-sized phone plug
Answer #2:
If you don’t have a home network already, you can still use Selkie to recover your files to a second computer. Ask you local computer shop for a cable called a “crossover cable”. This allows you to connect two computers together directly.
When you boot into Selkie, select “Advanced” mode when you reach the welcome box. Click “OK” until you reach the box asking you what type of network you would like to set up. One of the options is “Direct connection to another computer.” Select this option and just follow the text on your screen.
Hope this helps!