Who to download all available songs in iTunes Match with one click

Welcome to the Apple community Vincio.

Select the first item in your library, shift-click the last one to select all your content. ctrl-click on any selected item and choose download from the menu that appears.

Unfortunately, there is no button to download all songs at once, but you could download a whole album at once. Therefor just open iTunes and choose the album view, then click on the little "iCloud" icon in the upper right corner of the album art.

Edit: Winston's solution is better.