Putting on a headcollar:

Lets presume you have just finished riding and want to put your pony/horse in the field for some fresh air instead of stuck in a stuffy stable.  Its best to put your horse in the stable to prevent it from running off whilst putting on the headcollar though.

Take off the bridle - (Shown how in the page 'Bridles') and place it back in the correct place, or hang it over the stable door and put it back later. Then get your head collar to hand, and if you look at it you will see an area that is a circle shape. Place that over your horses' nose, and if you look you will see a strap with a buckle on hanging down.pull that up and under your horses' cheek and buckle it to the piece on the other side.

Shown below is the net of a headcollar to help you suss out what I mean.