The steps to use a pet chest strap are as follows

Prepare chest straps: First, take the existing chest straps and ensure they are in good working condition.
Placing chest and shoulder straps: Place the chest and shoulder straps on the ground to form an "8" - shaped structure, taking care to maintain a horizontal "8" instead of a vertical one.
Wearing the dog: Next, place the dog's two front feet into the two circles of the "8" shaped structure. If the dog is unwilling to cooperate, small snacks can be used as a reward to guide the dog through the wearing process.
Adjusting the chest and back straps: Adjust the tightness of the chest and back straps so that they are neither too loose nor too tight. Ensure that the chest strap does not get stuck under the dog's armpit or restrict the movement of their shoulder blades.
Fixed chest strap: Once the dog's forelimbs are worn, the strap can be lifted and adjusted to the appropriate angle to avoid getting stuck in the dog's neck or armpits. At the same time, chest straps should be able to effectively protect the chest muscles of dogs without affecting their free movement.
Buckle up: Wrap the buckle of the chest strap around the dog's back, and thread the rope of the buckle through the buckle on the back. Tighten the buckle from behind to lock it in place.
Check and adjust: Finally, check if the chest straps are properly secured and adjust the tightness appropriately to ensure the comfort and stability of the dog when wearing them.
When choosing chest straps, it is important to consider products with sturdy and durable materials to adapt to the high frequency of daily use. For dogs who attempt to use chest straps for the first time, it may take some time for adaptation. It is usually recommended to start training after the dog is about four months old and vaccinated, so that they can better adapt to this restraint method. If the chest strap is found to be unsuitable during use, it should be replaced in a timely manner to avoid injury to the dog.