Hey there! it depends on the context of the sentence. You can understand "there you go" literally, as describing somebody going somewhere, but as a saying it is an expression used non-formally when you give something to somebody. Like, for example, you pay your bill at a restaurant, and you give the money to the waiter and tell him "there you go" when you give him the money. "Here we go" should be understood more literally. You are describing that you are about to do something or go somewhere with other people. I don´t know, I guess the sentence is less meaningful in your native language than it is in others. I hope I could help. 祝你好运！

Here we go is something that you would say to a little kid if you pushed their swing at the park really fast. There you go is something you would say if you gave someone something.

This is a little difficult to answer without the phrases "here we go/there you go" being used in actual sentences. I can tell you that "again" often follows both of these terms and it's kind of a comical expression. For example: You just had to run though a huge rainstorm to get to the store. You finish your shopping and you get to the doors about to leave. You notice it's still pouring rain outside and you say to yourself, "Here we go again!"

Yeah it would be OK to say "here we go" on that situation.