You will need 3 measuring sticks and 2 clamps (large black office clamps work)

Take the 3 sticks and place them in an Upside Down U shape.

Take the 2 clamps and place them on the sticks to hold them in place

Measure from bottom of the top horizontal stick down 1"

Write 1" on the 2 side vertical sticks

Measure from bottom of the top horizontal stick down the vertical sticks at 10" down

Write 10" on the 2 side vertical sticks.