Below is a drawing of the Switch Harness noting where it was designed to be positioned on key body parts, along with where the closures and adjusters are:
Blue = Closure.
Pink = Slide Adjusters.

On your switch harness there are tags showing where the front and leg openings are:
Orange tags = Leg Openings.
Green Tag = Centre Front Waist.

* It may be easier see what goes where, by laying the bottom harness flat when opening to find these key areas to ensure nothing is twisted from being in the packaging.

Don’t worry if it’s not in the correct position when you first pop it on, you may need to do a little wiggle to get it in place. On the hips, waist and leg straps, you will find sliders where you can adjust the size to suit your body shape. Once you have everything in place and it fits to your comfort, this is now sized personally to you and it will be easier and quicker to get into next time.