It usually has a users manual on the cd that tells you the default IP address and default admin password are for your device.
As for security WPA2 is the security option to choose. Pick a good long key (12 characters or so, and mix in numbers etc. So, l0|Vgp@3sW{)rd is fairly secure, where as longpassword, is junk.) Also, change the default admin password right away. Make sure remote (outside the lan) access to the router is disabled, and make a note of the new password, as you will not use it very often, and it can be easily forgotten (I have my fathers router password written down for those rare occasions I need to walk him through something in his router, less then 1 time a year).