AOA

i have installed a DSL Connection last night,modem wifi hay but jab bhe main mobile say serch karta hun to network to show hota hay but mobile mujh say "Pre Shered Key" mangta hay? ya preshared key kya hay kaisay milay ge and agar main koe bhe entre karta hun to jab browsing start karnay k lea connect karta hay to ya error ata hay "no Gate way unable to conect.invalid WPA pre-shered key"

please any1 will tell me how to solve this issue

Regards