First and to simplify the process, make sure you already have created all the items that you want to add to a specific Modifier Group.
1. On our dashboard, on the left sidebar, click on " MENU " to access your "Modifier Group" page.
2. Now, choose to create a new Modifier Group or use an existing one.
3. On the search bar, below the question "Which products will have this modifier group?" you can search for all the items on your Menu and add the ones you want, all at once.