Belly putters are a great option for those players having a hard time making an arc with their putting stroke or have a hard time keeping the clubface square because they anchor the putter handle on the torso
Set up a board angled back and inward behind your ball and practice making your downswing to trace the angle of the board into the ball to assure that you are approaching impact from the inside
Impact position is the most critical point of the golf swing and you must understand it is not the same as address, the correct impact position is how you compress the ball, get backspin and achieve your desired ball flight