이 -> close to me. e. 이 커피 (this coffee)
그 -> close to the person you're speaking to or if it's something both speakers can't see e. 그 카메라 (that camera) 그 사람 (that person [that it's not here])
저 -> far from both speakers e. 저 레스토랑 (that restaurant [over there])
este, ese, and aquel if you know Spanish;
この, その, and あの if you know Japanese.
그 is used to refer to things close to the listener (e.g. That dog next to you), (or things you can't see, or neither of you are close to) and 저 is for things far from both you and the listener (e.g. That house over there). 이 is for things close to you, the speaker. :)
How come i put "this, that, and that over there" and it only marked me wrong because there was no "thing" on the 그 portion, but did not care about no thing at the other parts?
Because 것 is thing. It might have accepted this thing, that thing, and that thing over there
"This, that, and that over there" is now accepted. It was rejected because of the "and", and the algorithm must have considered it as a typo or something of "thing".