Just created a new DE, because my old one also had all these errors.

Trying to verify the create custom button link, but received an error also when testing the customize the page layout challenge. Any help?

Challenge not yet complete... here's what's wrong: 
There was an unexpected error while verifying this challenge. Usually this is due to some pre-existing configuration or code in the challenge Org. We recommend using a new Developer Edition (DE) to check this challenge. If you're using a new DE and seeing this error, please post to the developer forums and reference error id: 

Trailhead chhalendge:
Create a flow to streamline entry of new accounts, contacts, and opportunities.

error: 
UPSERT --- UPSERT FAILED --- ERRORS : (REQUIRED_FIELD_MISSING) Required fields are missing: [StageName] --- for SFDC record with ID : null,
 

Just created a new DE, because my old one also had all these errors.

Trying to verify the create custom button link, but received an error also when testing the customize the page layout challenge. Any help?

Challenge not yet complete... here's what's wrong: 
There was an unexpected error while verifying this challenge. Usually this is due to some pre-existing configuration or code in the challenge Org. We recommend using a new Developer Edition (DE) to check this challenge. If you're using a new DE and seeing this error, please post to the developer forums and reference error id: 

Please help!  I am stuck on creating flows.  Can't seem to work.  I keep on re-doing my work and not sure if I am doing it right.  The challlenge as follows:

To pass this challenge you will need to create a flow that implements the business process of Account, Contact, and Opportunity data entry and place it on a Visualforce page.The Flow will need to be called 'New Customer Flow'.
The Flow should have a screen with fields for First Name, Last Name, Company Name, Opportunity Amount, and Opportunity Stage.
The Flow needs to have steps to create an account, a contact, and an opportunity from the data entered.
Opportunity name, close date and stage are required fields. Name the Opportunity '{Company Name} - {Last Name}', set the close date to one month from today and set the stage to 'Prospecting'.
The Flow should be invoked from a Visualforce page.
The Visualforce page should be called FlowPage.
The Visualforce page will need a component to reference the 'New Customer Flow' process.

If possible, if you can provide a snapshot.

Thank you.

The challenge is:

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.

I start with Accounts when records is created or edited.
Filter criteria where accounts shipping address (street, city, state, zip code) is changed (used "or" logic).

I am stuck on the next step "add action".  I started with action type "Update Records".
On objects, I can't seem to change Accounts to Contacts.  Why?