How to set the shortcut on the face of the Apple Watch

Are you asking about having a complication show up on the main watch screen? If so you can long hard press on the home screen and then the main screen will minimize. Once minimized you will see an option at the bottom of the screen to customize. Click on the customize button. From there you can swipe to the right and you will be given overlay screens that let you decide which complication you would like to add or change. Click on the part of the screen that is outlined and from there you can update your complication. If the complication you want to change is not highlighted, click on the one you want to update.