A Chartroom spreadsheet comes fully-configured with all the software it needs to operate.
At all times you are the owner of your data. At various points you will be required to allow Google to run Chartroom software against your data. If you are happy to allow this then click Allow when these authorisation requests pop up. Note that some users may need to go through a slightly more complicated process – see the 5-minute Quickstart.
Google Sheets saves your work automatically, and periodically takes snapshots of the entire spreadsheet in the Version History. You can also make named versions of you charts at any time.
Chartroom's primary user interface is via a web browser and this may be all that you ever want to use. But once your charts have been created you can use the Google Sheets app on a mobile device to enter scores and run through to completion.