Mac equivalent of PC 'minimise all' then open a single folder? I save a lot of things on desktop. Often I have lot of applications and windows open and I want to simply minimise all and then drag a newly saved file from the desktop into a folder.

On PC it's easy. I just click the 'minimise all' button in the bottom right, open the folder I wish to drag to (usually from the taskbar), then drag and drop.

How would I do this on Mac OS X?
Bring Finder to the front. Minimize all other apps with altcmdH. Then alt-click on the minus-button of one Finder window to minimize all windows to the dock.

Reopen the destination folder by clicking on the appropriate dock (Finder) window icon located near the trash can and move or copy the file on the desktop (tested with 10.7.5 Lion and 10.10.3 Yosemite).
If you've enabled "Minimize windows into application icon" in System Preferences -> Dock previously, right-click on the Finder icon in the Dock and choose the appropriate folder to open it (tested with 10.10.3 Yosemite).