Good.

These are perfect examples. So you can use it when you arrive at a location (Here we are! We made it!)

or

You can use it when you have a final result, when everything comes together (He pulled the pizza out of the oven and said, "Here we are. Let's eat!" or ... The last boy got onto the school bus. The driver closed the door and said, "Here we are. Let's go!" or ... The girl reached over the table for the ketchup and put some on her hamburger saying, "Here we are! Much better!).

Here are more examples:

"Winter break is over and here we are again."

"So here we are, three years later. What's changed?" - This is interesting. It refers to a location in time, not physical location.

Can you think of other examples?

Erin

I don't know the exactlly meaning. I guess maybe it is like an auxiliary word or we are here now.

For example: I ask a question to a teacher. When she gets the answer on a book, she shows it to me and says "Here we are. Look at..." 

Also, I travel with my friends. When we arrive the place which we want to go, I can say "here we are."

Could you tell me if I'm right or no? Thanks.:)