The most common way you will see this done is to simply attach the outboard end of the spinnaker pole to the clew of the headsail. This downside to this method is that you cannot tack, gybe or stop the yacht quickly with this method. The true skill of a sailor is being able to bring the yacht to stop, without using the engine, whilst sailing. So, for instance, in a collision avoidance situation, man overboard or even just short handed the effort of trying to wrestle with a headsail flapping around with a non fixed spinnaker pole is undesirable.
A better method, using the spinnaker pole with a sheet and guy, though taking a bit more time to set up, has the advantage of letting you have full manoeuvrability of your yacht at all times.
The first part is to set up the spinnaker pole. This requires a pole uphaul, pole downhaul and guy, all attached to the pole to keep it fixed in position.
Set up a third sheet line, normally a spinnaker sheet. This connects to the headsail clew directly and it runs through the spinnaker pole jaw. This third sheet is lead back to the cockpit in the same way as a spinnaker sheet is lead.
When you wish to pole out the headsail, the spinnaker pole is set into position using the three control lines (uphaul, downhaul and guy) and locked off so it’s completely stable. The pole should be set so that is 90 degrees to the mast, in line with the headsail clew. The 3rd sheet line is winched in so that the headsail’s clew is sheeted home to the spinnaker pole jaw, you are now sailing with a poled out headsail.
If a change course is required quickly, the 3rd sheet can be eased off whilst you control the headsail using the headsail sheet leaving the spinnaker pole in place. This means you can now manoeuvre the yacht.
It is also possible to “sky” the pole, which is a controlled manoeuvre by releasing the 3rd sheet from the pole then easing the downhaul and guy, whilst hauling in on the uphaul. This allows you to bring the outward pole end up to the mast so that it is parallel with the mast. Just make sure any mast fittings don’t get damaged from this manoeuvre. With the pole skyed, and the 3rd sheet loose, the yacht can do any manoeuvre required.
If you wish to pole out the headsail again, reset the pole, re-run the 3rd sheet, and off you go.