This article explains how to use an Apple Watch and an Android phone together.
How to Use the Apple Watch with Android (It's Expensive)
To connect your Apple Watch to an Android smartphone, you'll need:
First, set up and configure your Apple Watch with your selected iPhone device. You’ll need to start with an iPhone to set up your Apple Watch and connect it to your carrier’s LTE network.
Once your Apple Watch is ready, continue with the steps below.