Thank you so much, I have this running now. I have added to the above details to do what I am aiming at. below is what I have now got setup
00 8 1-7,15-21,29-31 * * [ "$(date +\%u)" -eq 6 ] && this runs at 8:00am ONLY on 1st, 3rd and 5th Saturday of the month
00 8 8-14,22-28 * * [ "$(date +\%u)" -eq 6 ] && this runs at 8:00am ONLY on 2nd, 4th Saturday of the month