The term "we're" is a contraction or abbreviation of the words "we" and "are." The letter a is replaced by an apostrophe. This word is used to describe something that is either happening now or will be happening in the future.
If you have difficulty remembering when to use this particular word, check if you can replace the word you have chosen with the words "we are." If the sentence doesn't make sense, you need to use the word "were" instead.