title: Add VM Instance to an Instance Group
body: <p>I'm brand new to GCP and I'm trying to get an instance up and running. I'm noticing that the instance seems to be not healthy because the IP is not connecting. I want to check the health of the instance but I think it needs to belong to an instance group before I can do that. But I can't see how to add an instance to a group.</p>
  
  <p>Here is the UI:</p>
  
  <p><a href="https://i.stack.imgur.com/l1Cxe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/l1Cxe.png" alt="enter image description here"></a></p>
  
  <p>I want to add the <code>statcasters-instance</code> to the <code>statcasters-group</code> instance group. Does anybody know how I can do this?</p>