Pick a scene, tweak it, watch the preview, then copy the link into an OBS browser source. Everything is free and nothing needs installing.
Transparent: in OBS the page background becomes see-through, so aircraft and panels sit over your own map or camera. Chime: tick "Control audio via OBS" on the source. Public ADS-B and MLAT data only. Aircraft that switch off can't be seen, and positions can lag by up to a minute. Keep the on-screen credits visible (adsb.lol data is ODbL-licensed).