There are several things to do.
First we need to know what the cards chip set is. Open a command prompt and run the command
'/sbin/lspci' and post the results. This will list the devices on the PCI bus.
Next run the command '/sbin/lsmod' and post the results. This will list any modules ( drivers ) and are inserted in the kernel. Run the commands without the quotes. Post the results.
From there we can look for what module to insert, if it is not inserted already.
Next comes configuration. You need to find out things like - DHCP yes or no, DNS addresses, default route, type of encryption, the access point(s) you want to access. It would probably save time if you tell us the make and model of the router you are going to connect to.