You can open the Google Drive upload dialog via one of the following methods:
Once reaching the Google Drive upload dialog, you can choose assorted settings that will be applied to the uploaded video. After making your selections click on Link to Google Drive..., this will open the Google Drive Authentication dialog.
Once the Authentication dialog appears, login to your Google Account if required, and follow the prompts to allow the application to access your online profile.
After authentication is complete, you can click the Upload button to commence the conversion (if required) and upload process.