Exactly how do you envisage this working? Do you want to be saving the results of a filtered view or to just extract the full data-set?
Also, Why are your users not using the download button within Tableau Server?
I would like to save the results of a filtered view.
I want the filtered data to be exported into excel/csv by clicking a button.
It should be saved in a pre-defined location. Prefer this to be done in Tableau Desktop.
Details can be found here: The Greatest Tableau Tip EVER: Exporting CSV made simple!
However the only limitation is that is exports as CSV, but as for most users this will automatically opens up Excel and should not be a problem. It doesn't save to anywhere but the user's 'downloads'
You need to make sure the alphabetical first sheet in the dashboard is the one you want to export and apply the same filters to that page.