We are given with the steps:
To make a plain apron, first measure and write down the measurements below.
If you’re making an apron that will be tied, extend this length by at least 1 ½ times the measurement.
Decide how wide you’d like the waistband to be, adding 1 inch for the seam.
Decide how far down you want the apron to fall and measure that, adding at least 2 inches for seams and the hem.
Measure the width you’d like the apron to be from one side to the other, adding 1 inch for hems.
Cut your selected fabric in the dimensions you’ve written down.
The missing step is
To keep the edges from fraying, sew ¼ inch wide overcast stitch around the short ends.