I'm working on the 4th unit of the Lightning Flow module and as part of the flow I'm supposed to do the following but there is no SOBJECT VARIABLES | opportunity | StageName. to choose. It's not a challenge but as I am new to process builder/flow I'm trying to follow along with the instructions whether they include a challenge or not.

I built the process in my dev org as I couldn't find the correct fields in my THP. Now I'm stuck so any help would be greatly appreciated. I've been stuck on this for hours.

Clone the Opportunity
When the flow is called by the process, the {!opportunity} variable will contain fields from the original opportunity. Before we clone that opportunity, let’s update some of the fields. That way, the renewal opportunity doesn’t start off as Closed Won.
From the Palette tab, drag an Assignment element onto the canvas.
Name it Update Opportunity Fields.
Set the stage to Prospecting.
For Variable, select SOBJECT VARIABLES | opportunity | StageName.
For Operator, select equals.
For Value, select PICKLIST VALUES | Prospecting.

Thanks!
Cheryl

I'm working on the 4th unit of the Lightning Flow module and as part of the flow I'm supposed to do the following but there is no SOBJECT VARIABLES | opportunity | StageName. to choose. It's not a challenge but as I am new to process builder/flow I'm trying to follow along with the instructions whether they include a challenge or not.

I built the process in my dev org as I couldn't find the correct fields in my THP. Now I'm stuck so any help would be greatly appreciated. I've been stuck on this for hours.

Clone the Opportunity
When the flow is called by the process, the {!opportunity} variable will contain fields from the original opportunity. Before we clone that opportunity, let’s update some of the fields. That way, the renewal opportunity doesn’t start off as Closed Won.
From the Palette tab, drag an Assignment element onto the canvas.
Name it Update Opportunity Fields.
Set the stage to Prospecting.
For Variable, select SOBJECT VARIABLES | opportunity | StageName.
For Operator, select equals.
For Value, select PICKLIST VALUES | Prospecting.

Thanks!
Cheryl

Challenge Not yet complete... here's what's wrong: 
There was an unexpected error in your org which is preventing this assessment check from completing: System.DmlException: Update failed. First exception on row 0 with id 0060I00000UJtyaQAD; first error: CANNOT_EXECUTE_FLOW_TRIGGER, The record couldn’t be saved because it failed to trigger a flow. A flow trigger failed to execute the flow with version ID 3010I000000YTYA. Flow error messages: An unhandled fault has occurred in this flow
An unhandled fault has occurred while processing the flow. Please contact your system administrator for more information. Contact your administrator for help.: []
Does Anybody know the solution? 

I am beginner :  Not able to solve Trailhead challange for-Developer Beginner :Process Automation-Automate Basic Business Processes with Process Builder
"
Create a process to update child record when the parent is updated.
You've been given a requirement to keep Contact addresses in sync with the Account they belong to. Use Process Builder to create a new process that updates all child Contact addresses when the address of the Account record is updated. This process:
Can have any name.
Must be activated.
Must update Contact mailing address fields (Street, City, State, Post Code, Country) when the parent Account shipping address field values are updated.
NOTE: You may have to deactivate the validation rule for the Contacts object (created from a previous challenge) in order to complete this challenge."

 What I had tried 
Deleted validation rule on contact  from previous challange.
 Using Process builder created new Process with below details
Object: Account
Criteria:'Update Address' with condidtion

Field: selected shipping street, city, state,postalcode and country
Operator: Ischanged
Type: boolean
value: true

Condition:
Any condition met (OR)

 For Immediate action
Action name: Mailing address change
Records: Account.contacts
Criteria for Updating Records:No criteria—just update the records!

Set new field values for the records you update:

Field: selected Mailing street, city, state,postalcode and country
Type: Reference
value:  selected shipping street, city, state,postalcode and country

 after this saved and activated. So Once I check challange got below error:
"Challenge Not yet complete... here's what's wrong:
An update to an account record failed to update the mailing address fields of all child contact records. Make sure that the process is correct and that it is activated."

So Please help.