yes. xmas lights

I am brand new to all this, but what I want to achieve is to run 8 strings of lights from 8 gpo's controlled by 8 relays. I would like each string to come on and off at random independant of each other using a arduino mega. I am sure there is a sketch out there but I am chasing my tail with programming speek

Kind of like:

the hardware is what i am after, i am cool with that it's the sketch i am lost on. the one in the link i could not open. thanks. all information is welcome

Author stated code was:

thanks but honestly i did not understand a word of it, yes i am that new