Acorn’s video tutorials are based on Acorn 6, but they can definitely be used to learn Acorn 7 with notable changes between Acorn 6 and 7 highlighted on this page: Differences Between Acorn 6 and 7.
In Acorn 7.4 the clone tool has been updated to give you a preview of what your brush stroke will look like before drawing. In addition, a new on canvas widget is available which lets you know exactly where the source is coming from, which you can move around to pick a new clone source. Pressing the option key to reassign a clone location still works as usual. And just like the previous iteration of the clone tool, you can clone from other images or layers into any bitmap layer.