How to set up the Google Sheets integration
First, navigate to the campaign where you'd like to connect your Google Sheets account.
Click "Integrations" on the left side menu, and then choose Google Sheets.
On the integrations page, search Google in the upper right search box. This will pull up integrations with Google in the name, including Google Sheets. Then, click Google Sheets in the list.
This will open the connection page for Google Sheets.
Any previously connected Google Sheets accounts will be shown (if applicable).
To connect a new account, click the "Connect New Account" button at the bottom of the screen.
Next, you will see a screen which says "Application Connection would like to have |various permissions|". Click "Allow".
Finally, you will be prompted to select the account which you would like to connect. Check the box next to the appropriate account, then click "Save".
You will be able to select a tab of your choice from your connected Google Spreadsheet (tab selection is done within the widget's settings). Excel files are not supported, you would need to convert them into a sheet. Here's a quick guide on how to convert Excel files to Sheets.