So "il marche jusqu'à la plage" means something like "He walks to the beach (and he will stay there)" while "il marche à la plage" means "He walks to the beach (but he will not stay there)"? I'm not English and the difference in both languages confuse me
I remember a native explaining this to me. When you say "Le professeur marche jusqu'à la plage", you are saying that the teacher walks until he gets to the beach. When you just say "Le professeur marche à la plage", you are simply saying that he walks to the beach.
Presuming you're starting from the French, the "jusqu'à" tells you that he is walking (as far as, or right up until he gets there but no further) to the beach. "Walking toward" would be "il marche vers la plage". Hope that helps.