Listen to what others are saying. The most useful things you can be saying now are of air/air informational variety. Such as calling out enemy type/number/alt when you are the first around you to get them in icon range. Don't hesitate to call out check sixes rather than use the ingame check six function. Or, if you're not sure they're in immediate danger, simply say "_______, watch that (enemy plane type)"
EDIT- I should mention not to overdo this. Only notify if you think your countryman has not seen the bandit, or if the orientation or intentions of the bandit have changed and you think your countryman is unaware. Don't tell a countryman about an enemy they are already engaged with, or one that is clearly in their line of sight (LOS). To those who have been flying a while, situational awareness (SA) becomes second nature, and there are few things more annoying than having new players constantly restate what is already known.
Don't worry about base capture aspects just yet. They are complicated and personally I didn't quite care to learn them until I was about 7 months into playing the game. If you are a bit different and are very interested in the base capture aspects already, still don't worry about having to say anything yet. Learn a bit more.
But yes, certainly jump right into the air to air combat communication as soon as you want. As long as you are not restating the obvious, your information will be certainly useful.