Pull the metal tab to extend the tape measure. To make evenly spaced marks, you first need to make the initial measurement.
Look at the last whole number that is before the location of your measurement to find the inches. Count the small lines from the whole inch closest but not past the mark and you have your measurement in inches and sixteenths.
Mark the next evenly spaced measurement by placing the metal tab on the location of the initial measurement and extending the tape measure to the same distance as the initial measurement. Find the same whole number of inches and count the same amount of smaller lines to find the sixteenths.
Repeat as many times as needed to mark each equal measurement.