Can I create a Google Data Studio report without using a Joinr template?

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