I'm currently working on the below challenge, but I'm unable to complete it. Because I couldn't find the "override predefined actions" link.Please refer below screenshot

Simplify your brokers’ account layout
Your brokers also need a customized page layout for their accounts. To do this, click on Mobile and Lightning Actions for the Account Layout page layout, override the predefined actions, and then customize them.
In the object manager for Accounts, edit the Account Layout so that Mobile Smart Actions is the first item for Salesforce Mobile and Lightning Experience Action

I'm currently working on the below challenge, but I'm unable to complete it. Because I couldn't find the "override predefined actions" link.Please refer below screenshot

Simplify your brokers’ account layout
Your brokers also need a customized page layout for their accounts. To do this, click on Mobile and Lightning Actions for the Account Layout page layout, override the predefined actions, and then customize them.
In the object manager for Accounts, edit the Account Layout so that Mobile Smart Actions is the first item for Salesforce Mobile and Lightning Experience Action

I have tried this process builder challenge several times and different ways and still get an error message.  Here are the screenshots of what I am trying:



When I test the process it works, however, I get the following error message from the trailhead:
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.

Can you please tell me where I have gone wrong?