You can use the Align tool on the Form Design toolbar:
This only took a couple of minutes. First placed checkbox in A1. Then right clicked checkbox to copy & pasted in A2 - A4 not caring about position (they were pasted to far left of cell). With A1 checkbox in wanted position, selected all checkboxes (hold down Shift & left click each checkbox). Then use Align tool to align the left or right edge.