The kitchen table in issue Woodsmith 268 has long legs that require a notch in the top to hold the stretchers. To support the leg while cutting the notch you can use the jig you see in the drawing below. You need to attach a cleat to the face of the leg support to hold the leg in place while cutting the notch. Use the leg blank to mark the angle of the cleat on the leg support, then pin nail the cleat in place. The drawing below show this.