I would break the unit up into three main tutorials, leading to a culminating task. The first lesson would introduce the project with some cultural background and a look at the art history of the Picts and the Gaels. This would show students the cultural context of the work and how math and patterns are used in design- on paper and in stone.
The first lesson would end by watching a demonstration or video- the first tutorial. This would give students a chance to practice the initial exercises and create their first knot based on a simple rectangle.
A clear and easy to follow video can be found here, and a variation can be created for demonstration http://www.youtube.com/watch?v=xce8NSx3AKo.
The second lesson would start with a review of the first tutorial and the art history and then a look at the second tutorial. The students would then spend some time working in their sketchbooks on the next exercises.
The third lesson would build on the first two with a more complicated knot. This would be a longer project, lasting at least three classes- and ending with the submission of the culminating task.