The main website is https://pathagoras.mobi
If you do not yet have an account, download the free 30 day trial. You will be allowed access to the entire system, and granted a 5 user license. (There are no upload, download, document creation, bandwidth or other restrictions. You can work as if you own the program. You (or others to whom you provide credentials, up to 5) can simultaneously access all aspects of the program.
When you initially sign up for the trial, you will be asked to provide and confirm both your email address and a password.
For future use, click the Log On button (at the far right side of the home page). Provide your credentials where requested.
You can log on from any device and has as many simultaneous connections as you have licenses purchased (or for trial users, 5).
You can skip the home page and proceed straight to the log on page by adding "/app" to the above URL. E.g., https://pathagoras.mobi/app. Consider creating a shortcut on your desktop or a bookmark in your browser.)