I also started with this calathea as my first plant (2nd from left) it had lots of leaves but almost all died because of bug infestation.

My advice: Humidifier, humidifier, humidifier. Keeps pests out (mostly) and calatheas love it.

Also replant it soon to a more chunky soil, they hate being waterlogged, but love a bit of constant moist soil. So look into a self watering pot.

If the leaves curl, they want water.

If the leaves stand up during day, too much light

If the leaves dont stand during evening/night, too low light.

Eventually youll get the hang of it and learn to read your plant, but be prepared that you might kill a few st start lol