I deleted a couple of widgets, the wanting to re-add them I was stuck... I then tried to remove them all (hoping to reveal a hidden "add widget" link/button, but nothing. So now my dashboard is completely empty (the frontpage) - any pointer on how to add them again?
Click the button with the three horizontal stripes near the left edge of the screen. The slide-out menu has the names of the pages you can navigate to, and next to that is a > symbol. Mouse over that symbol for the widget you'd like to add, then click the Add to Dashboard button.