Using the substitution option on items is very simple, just keep in mind that substitutions are based on monetary value (equal or lesser value). Unfortunately, substitutions do come with some limitations (view video Function and Limitations of Substitutions for more information).
Step One: Login to the Orders2me Dashboard
Step Two: Go to the menu tab and select the category and item you would like to add substitutions too and click Edit.
Step Three: This is the most important step, click advance information:
scroll down and CLICK ALLOW SUBSTITUTIONS FOR OPTIONS
Step Four: Click Save Menu Item
VIDEO: