Watch faces offer an easy way to customize the look of your Apple watch. There are several faces already loaded on your Apple watch, including the digital and analog ones. This tutorial explains to easily change the watch face of your Apple Watch:
Tap and hold on the current watch face until the watch face gallery appears. From there swipe your finger across the screen of your device to discover the different watch faces (Utility, Modular, Motion, Astronomy...). Tap to select a watch face.
Some of these watch faces are customizable; you can for instance change text color, add weather information, add a calendar or alarm module, and display a secondary clock...). In the Watch Face gallery, simply tap on the Customize button appearing below a watch face to edit the latter. All the features that can be modified (using the digital crown) are outlined in green.