Within the putting setup, we’re trying to get the shaft and forearms to be on a similar plane, which will give us the best chance to make a relatively simply stroke that is on line.
After getting your forearms aligned with the shaft, bending from the hip joints with the arms relaxed. The ball position should be slightly ahead of center.
From there, you want to concern yourself with bringing the shaft back to where it started (or very close to it) so as to not add or decrease the loft of the putter. Making a smooth rotation of the upper body, allow the arms to swing freely beneath that pivot point.