Pairing is an introduction: a Bluetooth remote and its player exchange identities once, then recognize each other forever. Every brand performs the same ritual — a button held near the device until a light pulses — with the buttons varying. This guide gives the shared pattern; your brand guide on this site has its exact button pair.
The deeper explanation of infrared versus Bluetooth lives in the remotes explainer and is not repeated here. Compiled from manufacturers’ remote documentation.