Write an article based on this "Orient yourself with how the H-harness fits onto the cat. Place the harness on your cat. Check the fit of the harness. Let your cat adjust to wearing the harness."
H-harnesses have a strap that runs along the underside of the cat's chest between the front legs, in addition to the loops and the straight piece that a figure-eight harness has. If the loops of your H-harness are attached by two straight pieces on opposite sides of the loop, then you have a harness with a back strap and a chest strap. It is easy to identify the back strap because it is always shorter than the chest strap. Find the short strap (back strap) and hold this. Now slip the cat's head through the smaller loop. Unbuckle the large loop and you'll find one half of the loop forms a large D shape with the chest strap. Simply feed the front leg on the same side as the D, through the space within so that leg is enclosed. Feed the remaining long length of strap under the cat's chest and up the other side, and fasten the buckle. A good fit on a H-harness means that the harness is snug but loose enough to allow you to insert two to three fingers between the harness and the cat. It is typical, and important, that you spend some time adjusting the fit of a harness the first time you put it on. Use the sliding adjusters to change the size of the loops until you are satisfied the harness is fitting correctly. You want your cat to get so used to the harness that it forgets it's wearing it. Remember that not all cats will adjust to wearing a harness, so if your cat really puts up a struggle decide whether you have the time and patience for this kind of training.  To aid your cat's comfort, also let your cat sniff the harness and be around it for awhile before trying it on. This will make the cat more comfortable. Now you are ready to attach the lead to the harness and off you go!