Navigate to https://datastudio.google.com/.  Click on "Use it for Free"

Log in to your Google account. Be sure to enter the credentials which give you edit level access to your Google Analytics 4 property.

Once you are signed in, you will get a screen like below.  Select Create and then click on Data source

Select Google Analytics from the available data sources

An overly will appear like below.  A list of Google Analytics accounts will display.  Select the account that has the Google Analytics 4 property.

Select the GA4 property that you would like to connect, now click Connect

In the below screen you can choose to modify or define new schemas.

 Last, you will select Create Report and you are all set to start your Data Studio report creating.