In order to hard reset a Apple Watch 38mm, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Apple Watch 38mm device will be brought back to the default configuration of a brand new device.
1. Start by pressing and holding the Side button until the Watch Options pop on-screen.
2. Tap your finger on the Power Off option. Hold it down for roughly five seconds.
3. Afterwards, tap the Erase all content and settings option.
4. Voila, the Apple watches' hard reset is now ongoing.