Hello LondonBoulware999,
You can find the needed steps on how to join a FaceTime call from a Windows device here: Join a FaceTime call from an Android or Windows device - Apple Support
As the page notes, you'll need to use the latest available version of Google Chrome or Microsoft Edge, and have a strong Wi-Fi connection.
We've also listed the steps from the page here:
How to join a FaceTime call on the web
1. If you receive a link to a FaceTime call, open the link.
2. Enter your name, then select Continue. You might need to allow FaceTime to use your microphone and camera.
3. Select Join. Then wait for the call's host to let you in.
4. Select Leave to leave the call.
Cheers.