In the the tutorial example: Hello. My name is [Your First Name] from Acme Wireless
Customer Relations. How can I have show my First name when I run this flow?

Being new to Flows I would like to know how to handle an error in a Flow Trigger. I have a Workflow rule set up which triggers a Flow Trigger, passing the Opportunity record to the Flow Trigger. In this Flow Trigger I loop through Opp Team Members and update a flag, then update these and adding a new entry. What I need to capture however is if no record is found and the Lookup User step to find the new person to add to the OTMs returns a null value. 

I get the error email:
Encountered unhandled fault when running process Update_Opp_TM/301O00000004Ltt exception by user/organization: 00DO0000000VuvS/{4} Source organization: 00D90000000tgIp (null) UPSERT --- UPSERT FAILED ---  ERRORS :  (REQUIRED_FIELD_MISSING) Required fields are missing: [UserId] ---  for SFDC record with ID : null,
 
caused by element : FlowRecordCreate.Create_FollowUp_OTM
 
caused by: UPSERT --- UPSERT FAILED ---  ERRORS :  (REQUIRED_FIELD_MISSING) Required fields are missing: [UserId] ---  for SFDC record with ID : null, 

This is my Flow Trigger:

Before it does the Record Create I need to handle the error - it just needs to ignore the error and stop the flow.