Model Driven App Dummy Data

I had added the premade tables accounts, contacts into a dev environment and created a new model driven app and added these 2 pages and there was a bunch of dummy data already there, account names, addresses phone numbers addressed including timeline activities etc...

I now made a sandbox environment and tried to to do the same thing but the premade tables are empty of dummy data.

Anyone know what is going on and how I was able to get all that dummy data ?

Thank you