Newbie to the Board & to Audacity - Laptop has no line in...

That little thing in the middle is a Behringer UCA-202. It’s a USB stereo interface both directions. It has local headphones and has been certified for Overdubbing/Sound-On-Sound.

I have two.

This is one in a series. The UFO-202 has a phono preamp inside and used with old format, analog turntables.

And other people make adapters.

https://forum.audacityteam.org/t/sound-card-reviews/8375/1

Whatever you buy has to explicitly say Stereo or Stereo Line. There are adapters such as the Startech ICUSBAUDIO…

https://www.startech.com/Cards-Adapters/Sound/USB-Audio/Audio-USB-Adapter~ICUSBAUDIOB

Which seems like a nice unit and some of the ads say “stereo,” but it’s only stereo playback, it won’t record stereo.

Koz