You can create reports with multiple data sources; it will let you, for instance, have all your social media or ads data in the same view, as shown below.

Google Analytics and Google Search Console report.

Social media report (Including Facebook, Instagram, and LinkedIn).

To change the data source connected to your charts, click on the chart you want to modify, go to the Data tab and go to Data Source.

There you can see the data source connected to the chart. In this example, it is Facebook Ads.

Click on the data source (i.e. the gray element displaying the data source's name) and it will show you a list of all the data sources you can connect to the chart.

Choose a different data source.

Heads up: If you don't see the data source you want to connect, but you already added the new data source to the report, we suggest you refresh Google Data Studio, and you will see it.

Once you switch the data source connected to your chart, you only need to replace the metrics and dimensions.

Change the data source on multiple charts in a bulk

If your reports have many charts, changing the data source for each one is tricky.

Google Data Studio lets you do this change in bulk in two ways:

Hold down the cursor and select multiple charts
Select every chart individually and keep shift pressed

Once you change the data source, such a change will be applied in all the selected charts.

More about managing data sources on Google Data Studio: