|If your wireless network is protected, at some point you will need to enter the special key required for this to have access. It would have been setup on the same computer, with the old OS installation, but the key is stored in the router/hub/whatever. |
If you don't have a protected network, you can skip this (but it is advised to protect your network anyway).
After that, it should be easy, let him try to find an IP (don't set a fixed one), and set Subnet mask to 255.0.0.0 or so