You start at the top of the data set. You press Ctrl+Shift+DownArrow and Ctrl+Shift+RightArrow. This is great… you’ve selected the whole data set, but now how do you get back to see the top of the selection?
Press Ctrl+Period twice.
Each press of Ctrl+Period keeps the current selection but moves to the next corner (in a counter-clockwise direction). So, if you are currently at the bottom right of the selection, press Ctrl+Period twice will get you to the top left corner of the selection.