"where" is used for locations/places/directions. (in French: where = où). "which" is used when there are a few possible choices and you want to refer to only one of them. (in French: which = lequel/laquelle/lesquels/lesquelles). ex: Please tell me where is the Hotel Royal. I am not sure which color to choose (red, blue or yellow). Do you have a specific phrase that you find confusing?

In English grammar there are 5 relative pronouns: who, whom, whose, which, that. Who refers to people. That and which refer to groups or things. Examples: Anna is the one who rescued the bird. Luke is on the team that won first place. She belongs to an organization that specializes in saving endangered species. Rule 2 That introduces essential clauses while which introduces nonessential clauses. Examples: I do not trust products that claim "all natural ingredients" because this phrase can mean almost anything. We would not know which products were being discussed without the that clause. The product claiming "all natural ingredients," which appeared in the Sunday newspaper, is on sale.

"where" is an adverb meaning the foillowing: 1. in or at what place?: Where is he? Where do you live? 2. in what position or circumstances?: Where do you stand on this question? Without money, where are you? 3. in what particular respect, way, etc.?: Where does this affect us? 4. to what place, point, or end? whither?: Where are you going? 5. from what source? whence?: Where did you get such a notion?