To begin, look at the teeth around the circumference of the pulley. There is a portion where about 4 teeth are missing, forming a gap (this is not shown in the picture). Move the pulley until this gap sits under the head of the Crank Sensor.

The triangular mark on the pulley should now be carefully lined up with the bottom edge of the pointer using small movements of the crank. If you want to establish that Cylinder 1 (Front Cylinder) is in the TDC (firing) position you'll need to look at the cams. Their timing notches are only visible with the cam cover removed, although it is possible to see the cams opening the valves on No 4 cylinder which indicates No1 would be firing. It might be wise to put a mark next to the No 1 TDC firing triangle on the pulley using Tippex (White) or similar to make things easier, but don't obliterate the mark itself.

The red arrows point to the traditional Jaguar timing notches in the cams.

Both of these should be pointing upwards at 90 degrees to the head face. If you are just checking timing then a visual check will do, but if re-timing the cams you'll need the setting gauge to position them accurately.

I've set this one just a little low of centre just to make things clearer. Adjustment of the cam sensor is easy, loosen the bolt in the block and rotate the sensor body to get the dimple positioned in the middle of the window. Now and then, you may find a car with the dimple set 180 degrees out from No. 1 firing, in which case you'll have to pull the whole sensor out and reposition it.

There is s very helpful second dimple struck on the side of the rotor (not a complete dimple) to help with this. Set this second dimple beside the centre of the window. When inserting the cam sensor the main (centre) dimple will line up in the window when the helical drive gear turns the rotor as it engages.