Every serve, out loud, in this order: your team's score – their team's score – server number .
If you forget to call the score, opponents can ask for it. If it's called wrong, either side can correct it before the return of serve.
When your team wins a rally while serving, you and your partner swap sides. When you lose the rally, you stay. That's the whole rule — the score tells you where to be.
Two servers per team, per turn (except the very first serve of the game):
The 0–0–2 start exists so the team that serves first doesn't get two turns before the other team has served at all — it's a fairness rule, not an exception.
Some tournaments and leagues (notably MLP) use rally scoring :