If you use CameraFTP apps or CameraFTP.com website, you can use "Sign in with Google" to log in. If you only need to download a few files, you can log in to www.cameraftp.com, go to My Cameras page, then click the folder icon below your camera thumbnail. You can locate the file(s) in the camera folder, check the checkbox(es) and click Download to download a single file, or download multiple files as a zip file.
If you want to download a lot of files, or download the entire camera folder, then you can use an FTP client such as FileZilla. You cannot use "Sign in with Google" with an FTP client. In this case, you can:
(1) Use the camera's FTP password. Just log in to www.cameraftp.com website, click the Settings icon below your camera thumbnail. If the camera is bound with a camera license, then you can find the FTP password associated with the camera license.
(2) Set your regular account password. Log in to www.cameraftp.com, go to Account Details page, click Change My Password. You can then log in to CameraFTP directly with your CameraFTP username and password.
For downloading camera footage, you can also watch the following tutorial video:
https://youtu.be/9GCtngFaw4c