If you are facing the problem shared in the image ; Félix Adorno (RK Rivera)

already provided the solution to this event. 

Here are the steps that worked for me:

1.  From the App Launcher, open Data Cloud, then go to the Data Governance tab. 
   •  If you don't see Data Governance or can't manage policies, you may need to assign your user the Data Cloud Architect permission set. 
   • To be able to assign Data Cloud Arquitect permissions to your role ; do as follows:
     • Open Setup: Click the gear icon (⚙️) in the top right corner of the screen and select Setup.
     • Search for Users: In the left sidebar, use the Quick Find box, type Users, and select the Users option that appears in the results.
     • Select the user: Find and click on the full name of the user who needs the permissions (e.g., your own user account).
     • Edit Assignments: Scroll down the user's profile page until you find the Permission Set Assignments section. Click the Edit Assignments button.
     • Add the permission: In the left box (Available Permission Sets), find and select Data Cloud Architect. Then, click the right-pointing arrow (Add) to move it to the Enabled Permission Sets box on the right.
     • Save your changes: Click the Save button to apply the new configuration.
2.  Go to Policies. 
3.  Delete the default policy that was automatically created for the playground. 
4.  Click New. 
5.  Select Data Access, then click Next. 
6.  Enter a Policy Name and set Authorization Level to Internal User. 
7.  Click Next and configure the rule as follows: 
   • Resource: Object 
   • Action: Allow access 
   • When should this action take place?: All Objects 
8.  Go to Users and, under Who should be affected?, select All Users. 
9.  Click Save and Activate.