I'll go into more detail, then. Hamon is a martial art that focuses around mastering the body and harnessing the power of the sun to fight vampires. By controlling their breath, Hamon practicioners can enhance various biological aspects of their bodies, like nullifying pain or slightly extending limbs by disconnecting joints temporarily. They can also infuse and transfer energy through objects. Water is especially effective for this - Hamon is also known as "the ripple" since energy transfers like the ripples in a lake. In the first demonstration of Hamon, a user was able to strike a frog sitting on the rock, transfering all of the power to the rock and shattering it, leaving the frog unharmed. It's very effective against vampires and undead by transfering life energy into their bodies and destroying them.
Stands, meanwhile, are a manifestation of a person's spirit, said to be comprised of the same life energy Hamon users tap into. It's called a Stand since the spirit stands next to you when it appears. Only Stand users can see Stands, and they tend to subconciously attract each other. Those who can't see Stands usually consider their activities to be paranormal, like upset ghosts haunting a house to use an example. Stands are usually humanoid but can come in a variety of strange designs and configurations that represent the kind of spirit the user has. Their powers usually reflect the user's hobbies or personality traits, but they manifest in strange ways. Some of them include supernatural reflexes, freezing time, summoning small bodies to kick bullets towards targets, diving through ground as if it was sand, creating portals that can be unzipped via huge zippers, and so on.
Stands have several rules that govern them - only Stands can hurt Stands, any damage a Stand takes is transfered to the user as well, and they must be maintained with the user's breath. Furthermore, just because a Stand can't be seen by normal people doesn't mean its powers can't manifest in the real world in a variety of ways.