I have a netgear modem adsl2 how do you hook up

SOURCE: connecting to x-box through a netgear

If your Xbox isn't seeing the SSID odds are your Netgear is set for Wireless N only.
http://support.xbox.com/support/en/us/nxe/kb.aspx?ID=967990&lcid=1033&category=hardware

Xbox is not compatible with Wireless-N only networks, so first step will be to make sure that the Wireless Mode on the wireless tab of your Netgear isn't set for 802.11n (you can pick the G/B or whatever other combination is listed there. In terms of performance you are not likely to cap even the lowest settings[wireless b] since 11Mbs is still decent speed and likely more than what you are given by your ISP).

(This is on page 21 of manual below)
ftp://downloads.netgear.com/files/DGN2000_SM_20May08.pdf

The other thing you will want to check is that if you have secured your Wireless network, the Xbox adapter is compatible with WEP(which is terrible) and WPA, not WPA2.

SOURCE: Could not make router to work, Netgear modem adding router.

i suppose you have to connect modem to router's "source" socket and modem to socket "in wall" then reset and reconfig router and you should be ok