Short answers, pulled from the story.
High-pressure areas form through downward motion across the troposphere, particularly beneath the western side of upper-level troughs. The two main origins are cold polar air masses spreading into cooler neighboring regions and atmospheric subsidence, where large masses of cooler, drier air descend from above.
High-pressure systems rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. The Coriolis effect, produced by Earth's rotation, bends the outward-flowing winds in those respective directions.
The highest barometric pressure ever recorded on Earth was 1085.7 hPa, measured at Tosontsengel in Zavkhan province, Mongolia, on the 19th of December 2001.
The Siberian High is a land-based, cold-core high-pressure system that can remain nearly stationary for more than a month during winter. It is somewhat larger and more persistent than its North American counterpart and drives intense northerly winds along the Pacific coast, generating a winter monsoon.
Subsidence in high-pressure areas dries the air through adiabatic compressional heating, preventing cloud formation. Without clouds to reflect incoming solar radiation during the day or trap outgoing longwave radiation at night, skies remain clear.
The subtropical ridge is a warm-core high-pressure belt near the 30th parallel, also called the horse latitudes, that forms as air rises near the equator, cools, loses moisture, and descends poleward. It moves north in spring and retreats south in fall, and many of the world's deserts are caused by these high-pressure systems.