For your own safety and comfort and that of your stock, I highly recommend that you train your horses or mules to horse hobbles before going into the backcountry. Below I have outlined a very basic procedure that should quickly and easily accustom your horses and mules to hobbles. Regardless of whether you will be using two-leg hobbles or picketing your stock with a single hobble, the first step will be essentially the same.
Before you get started, make sure that you are starting out with safety of both you and the horse as a priority. Make sure that you are in a safe space with good footing. There should not be anything that your horse or mule could step on or get wrapped up in. It's also best if your horse has been exercised first. A "hot" animal can be difficult to train. Do not try to start your horse with hobbles if it is already injured in some way. Set aside a large enough time frame for each session that you will be there without distractions the entire time (and safely out of the way should there be a blow-up). Finally, be patient. All good training takes time, and training a horse or mule to accept hobbles could take several sessions over one or two week's time.
Once you feel you are ready, make sure that your animal is okay with pressure on the front leg. It's easiest to run a soft, thick rope around one leg and (do not loop it, just have ahold of both ends of the rope). Gently pull on the rope until the horse takes a step. Release the pressure, praise the horse, and do it again on both front legs until you can "lead" the horse this way. If the horse gets frightened, don't pull; simply let go, calm the animal, and start again. I recommend that you do not move past this point until your horse is relaxed.
For two-leg hobbles, I recommend waiting a couple hours past normal feeding time and then putting your stock in a corral or round pen with a flake of hay. While they are eating, attach the hobbles to the front legs and give them a tug so that your horse or mule knows he is restrained. Because horses tend to think more about their stomachs, the initial hobbling experience will be a little less traumatic than a first time attempt in the backcountry. You can spread the hay out so that your stock has to walk around and realize that he is restrained. This process should be repeated to ensure your stock is comfortable with being hobbled before taking a pack trip.
For a picket hobble, once again wait a couple hours past feeding time and put your stock in a corral with a flake of hay. Attach the picket (single leg) hobble to a front leg and the picket rope to the hobble. Allow him to drag the picket rope without the picket pin attached until he is used to it. When you stake him out on grass or hay for the first time, take him out to the end of the rope and let him know he is restrained. Be sure to drive the pin straight into the ground. Your stock could pull out a pin driven in at an angle. If you horse is hungry, he should be too preoccupied with eating to have a bad first experience. This process should be repeated to ensure your stock is comfortable with picketing before taking a pack trip.