Six (6) or more Orbs Trigger the Re-Spin Free Spin feature!
Figure 1: 6 orbs appear on the screen marked by yellow boxes
You need to tap on any three (3) blank positions to activate the 2X reward feature. After picking the three (3) blank positions, tap on the "Play" button to trigger three (3) Free Spins.
Figure 2: Blank positions
Figure 3: 3 blank positions were chosen