Checklist Module - formula for adding selected date to date field

Checklist Module - formula for adding selected date to date field

Good afternoon, 
Although I've been a user of ZOHO CRM for a couple of years however, I don't have much experience with the correct syntax in formula fields. I do have a frequent need for automatically inserting an execution date upon certain field operations. But I have not been able to find any examples or support for this assumed, simple functionality. 

I'm in need once again for a new Checklist module I'm creating and wondered if someone may be generous with their time to help. I'm assuming the syntax for the function isn't too complex?

Checkbox Field: Pay_Statement
Date Field: Date_Received

Formula: when Checkbox is selected, current date is input into  "Date_Received" field ( I have no need for time)  - output as Full month name, day, year would be nice but not necessary.

Thanks for your help. I'm always happy yo return the favour,
Steve