Complex sentence: Traveler curtains are suspended on a series of short chains called "trim chains" that hang from rollers or "carriers", each with two wheels secured inside a metal "channel" or "track".
Split into simpler sentences: Traveler curtains are suspended on a series of short chains called "trim chains". Each trim chain hangs from a wheeled assembly called a "roller" or "carrier" that is supported by and rolls along the inside of a horizontal metal "channel" or "track".