So I'm trying to select a melody in piano roll and then clone it an octave lower underneath it, whats the best process? is it the pattern tool or should I be doing it using a different tool? I tried using pattern tool but it only seemed to let me paint it to the right of the original data

Drag it or copy and paste.
 
The manual is helpful to go over some basics from time to time in between your work.
Sonar Manual