This is the 627th most frequent Spanish word.
próxima
Next; upcoming.
In this sentence, 'próxima' is used as an adjective that describes the noun 'semana' (week), indicating temporal proximity, meaning the week that follows the current one.
La próxima semana viajaré a Madrid.
Next week, I will travel to Madrid.
Here, 'próxima' describes the noun 'estación' (station) and indicates spatial proximity, referring to the train station that is closest in distance.
La estación de tren más próxima está a cinco minutos caminando.
The nearest train station is five minutes' walk away.
In this context, 'próxima' is used as an adjective modifying 'clase' (class), specifying the subsequent occasion of the described event.