Another new device is yet another device that needs updates. On such a small device you’re probably wondering how you do that?
First connect your iPhone to Wifi, and start the Watch app. In the “My Watch tab”, go to General -> Software Update.
Hit “Download and Install”, agree to the terms and install.
You’ll need to make sure your Watch is charged at least 50% and have it charging while the updates install.
Your watch will show you the progress so you’ll know when it’s done.
Make sure you don’t start the updates before you need to go out as it’s hard to know exactly how long they will take.