You can use a wooden skewer or something like that to check moisture deep down in the pot. If the soil is very fast draining (which would be best) it's really difficult to over water a Monstera. Just make sure the bottom of the pot isn't sitting in any water that's drained out. They like strong light but depends on where you are, sunlight can be stronger or weaker in different places. Tropics have the strongest (except if it's an overcast day).

Hi Ahmed, good news is these must be one of the easiest plants to look after, and your adopted one already looks healthy. They aren't very fussy, but I find bright but filtered light is best. I let the surface of the soil become dry to the touch before watering again, and as tropicbreezent says, don't let the pot sit in water. I also mist mine daily - although opinion is divided on this. Good luck and let us know how you get on!