Yes, a Joinr data source can added to any Google Data Studio report.
Note: If you haven't created a Joinr account and/or connected at least one data source, do that first > Getting Started with Joinr
Add the Joinr Data Source to a blank report
- Sign In to Google Data Studio
- In the top left, click Create, then select Report
- The Add data to report page appears, with two tabs
- Under the Connect to data tab, search for "Joinr"
- Click on the Joinr connector
- In the connector, click Authorize
- A pop up will appear. Sign in with your Joinr credentials
- After authentication, click Add (at the bottom right of the screen).
- The Joinr data source has been added to your blank report