We can't find an escalation action with Age Over set to 1 hour. Make sure the Age Over value is set to 1.

@Divya Manglam  

For Step 9, the issue is usually User visibility, not the escalation rule.

Check Setup → Sharing Settings → Organization-Wide Defaults → User and make sure internal User access allows Public Read Only. Then return to the Assignee Lookup and search for your active user.

Also verify that your Trailhead Playground user is Active and has the required access. Once the user becomes searchable, Step 9 should allow you to select your name.

This is a common Playground visibility issue rather than a problem with the Trailhead step itself.