Entire video project build available on YouTube (https://youtu.be/TBmi4iF6UGA)
Steps:
Cut 2 of the step_stool_v1.svg files
Cut 1 of the top_layout_v1.svg files
Cut 1 stretcher bar with an on tool rectangle to whatver width you find pleasing.
Rotate the stretcher and sides 90 degrees to cut on end. There are 2 files attached. If your material does not match mine, then just "center them when you place it.