The Date the activity actually happened field is a system field on Makerble. You do not need to create it, you simply need to add it to your survey by selecting it from the Public Questions Library.
Steps
Add the field to an existing survey
Select My Apps in the top menu
Select Surveys (if you do not have this option, follow these steps to access the survey editor page: Go to the Survey Editor page)
Use the Surveys Used By toggle to select a project that the survey appears in
Click the View Questions button
You arrive on the survey’s profile page
Click More Options
A dropdown menu appears, select Edit
You arrive on the Survey Editor page
Scroll down to the Public Questions Library in the left sidebar
Click the Add button next to Date the activity actually happened to add that field to the Survey
Scroll to the bottom and press Save
You arrive back on the survey profile page. That’s it. That field will now be available on all the survey campaigns based on that survey.
Now that the Date Happened field has been added to the survey, you, colleagues, contacts and survey respondents can use it to change the date of a story while creating or editing a story or submitting a survey response: How to backdate a story or survey response
Add the field to a new survey
Click Create in the top menu > A dropdown menu appears > Select Show More Options > Select Survey
You arrive on the Survey Editor page
Name the survey
Scroll down to the Public Questions Library in the left sidebar
Click the Add button next to Date the activity actually happened to add that field to the Survey
Scroll to the bottom and press Save
You arrive back on the survey profile page.
To use the survey, add it to one or more projects
Once the survey has been added to a project, you, colleagues, contacts and survey respondents can use it to change the date of a story while creating or editing a story or submitting a survey response: How to backdate a story or survey response