(Note: the following instructions refer to Yahoo! BB's series of white 'standing' modems. If you have one of the black types, references to the number of lights from the top will be from the left on your modem. Also, things change from time-to-time so what you see might be a bit different. )
Before trying to install the Wireless LAN Router card, you should make sure you have a link with Yahoo! BB's server. Connect the modem's power and yellow wires as shown in the instructions (power to the round hole hidden behind a paper label at the bottom of the back of the modem and the yellow wire from the yellow port to the phone jack on the wall).
Wait about 2 and a half minutes until the lights settle down. If all is well, the 1st, 5th and 7th lamps should be glowing steady. Others may also be on or blinking. If the 5th lamp (LINK) is not glowing steady, then thre is no reason to proceed as you're not conneting to Yahoo's server and that must be resolved first.
Installing the Wireless Router Card
First thing is to install the wireless card in the modem. YBBWIRELESS has posted instructions for that part here. To his excellent instructions, I would add the following.
Before inserting the card, disconnect the modem from the power by pulling the round plug at the back of the modem.
Next, you have to be sure the card is inserted the right way around and then make sure it's properly seated in the slot. Looking at his pictures you will notice that, when looking at the front of the modem, the two tiny lamps on the card face to the right.
The card must be pushed rather firmly to make it go the last several milimeters. When it is properly seated, the edge between the black plastic and the metal should be just about even with the top of the slot and the two tiny lamps are just visible above the side of the modem (see the 4th picture in the link above).
After the card is seated, plug the power back in and wait about 2 and a half minutes while the modem starts up.
If your computer's wireless card is properly configured, you should now be able to connect and surf. (I'm assuming here that the modem has already been connected to the wall jack and the LINK lamp (5th from the top) is glowing steady.)
If your computer side card needs configuration, your computer's built-in Help and/or the instructions that came with your wireless card should be used to configure that device.
Note: For use on the PC side, Yahoo! BB also throws in either a USB stick or a PC card at no extra charge. Those devices do not seem to have drivers that will work with English version Operating Systems, so they are not mentioned on my site or in advertising except to note that they won't work.
All the items in the Wireless LAN Pack must be returned to Yahoo! BB so I suggest you leave those extra bits in the box so you'll be able to find them when you stop using the service.
Securing your Network
Next, to make your connection secure, do the following:
NOTE: You must connect to your Yahoo! BB modem BY **WIRE** (included) to do this configuration.