It means "we've performed an action successfully". Say we fixed a broken computer, while it was booting we'd say "there we go".

Great explanation! I think it's worth mentioning that, for non-native speakers, this is easily confused with "there you go" which has several meanings: 1 - similar to "there we go", like when you're watching somebody succeed at some action, like starting up that computer or even more often if you're showing someone how to do something and they finally manage to do it 2 - when you're handing something to someone 3 - in an argument or discussion such as "there you go again with your crazy ideas" There is also "here we go" which is most often used as an annoyance over a repeated action, like that guy who always asks retarted questions in a meeting. As soon as he raises his hand, you whisper to the person next to you "here we go-oh"