Many models convert by using adjustable backrests with multiple recline angles, hidden pull-out sleeper frames, or chaise/lounger sections that fold or flatten into a bed.
Assembly varies by model: some require adult assembly with tools provided, some advertise quick/easy setup, and at least one listing notes no assembly required. Check the product listing for exact assembly requirements and included hardware.
Some models include extra-sleeping or storage features such as a pull-out trundle bed, side lift-up storage drawers and built-in open shelving; others offer smaller options like side storage pockets for phones or remotes.