Answer by
LeheckaG (1826)
First, research your local-building/zoning-codes,
specifically set-back requirements & water-rights.
Take measurements & draw up a plan. You want to circulate water to reduce algae, insect larva, & freezing, and aerate water if you plan to stock fish. Excavate your hole & seal it with a plastic-liner or concrete. Decorate or plant around your pond. You might require fencing around it.