You've just cleared the Demo Data from the file. Before starting the custom configuration process, it's a good idea to make a "_blank" copy of the file. This will allow you to start with a blank copy if you need multiple instances of the file in the future.

With the File Template open select "File > Make a copy". Alternatively, in Google Drive, right click on the file and select "Make a Copy"

Rename the file ZAP_b5_BK_PN_blank_{yyyymmdd}

NOTE: At the end of the file-copy process in the video, it would have been a good idea to click on the NAV1 > Refresh button to authorize the file just to make sure the connection was good and it was fully functional. You know how to do that from the BK Download Guide and you can either do that or not now. Every time you make a copy of this blank copy for use you will need to Authorize the new copy made as well.