To add GPT to Google Docs using the GPT Plus Google Docs add-on, please follow these steps:

1. Open your Google Docs document.

2. Click on “Add-ons” in the top menu.

3. Select “Get add-ons” from the dropdown menu.

4. In the Add-ons marketplace, search for “GPT Plus Google Docs” or a similar keyword related to the add-on you want to use for GPT integration.

5. Once you find the add-on you want, click on it to open its details.

6. Click the “Install” button to add the add-on to your Google Docs account.

7. Follow the prompts to grant necessary permissions and complete the installation.

8. After installation, you should see the add-on listed under the “Add-ons” menu in Google Docs.

9. Open the add-on, configure any settings or options if required, and you should be able to access GPT functionality within your Google Docs document.