Mathcad gateway and how to save it

I am interested in using Mathcad Gateway and have some questions. Mathcad Gateway runs on the internet and you are just accessing the files through the page, but do not modify the file itself. The file stays on the server.

If I have a calculation sheet with a lots of input how can I save it? Can I save it?

If some time later I need to change one number and run it again do I have to type in all the input values meaning that I start from sketch?

Is there any way to have a saved copy of the input on my computer?