Here's the thing: when you carve the guilloche itself, you commit yourself to cuts in the wood; you don't have a delete button or eraser! So, before tackling the repeated pattern of the guilloche itself, I think it's a good idea to pull out the various elements and practice, and there are four, which I take in turn and look at what's involved.
Even if you have no intention of carving guilloche, these are great exercises!