This is a very useful stop as it connects L3, L2, and the Funicular de Montjuïc. There are two levels, so don't pay attention to Google Maps walking which will have you wandering around on the surface level. Also, don't get onto one of the regional trains, unless that's what you're planning to do.
https://www.tmb.cat/es/barcelona/metro/-/lineametro/estacion/323
https://www.touristlink.com/spain/funicular-de-montjuic/overview.html read more