how to use cheat code from cobra 1.5 with viper gc

i have a gamecube with the viper gc chip with cobra 1.5. My question is How do i use cheat code? i thaught it was like action replay but it's not. Do anyone know a site with the code number? or any info would be great.

i know there's a problem call GCNCrypt to decrypt the code, i enter that and use it but it's still didnt work, am i doing something wrong?