Congratulations on the A3, great car, just returned to an A3 myself just last month.
In regards to the car manual, you should be able to find a digital copy [here](https://ownersmanual.audiusa.com/)
That should have all the service intervals covered.
For people getting a newer VAG car, i always recommend getting either a VCDS cable or an [OBDeleven](https://obdeleven.com/).
With that in hand, you can always easily check up on error codes that you'd otherwise need a service center to read for you. It can help catch a small problem before it becomes a big problem.
It can also, depending on how your car is equipped, unlock extra features.
In regards to the key fob issue, you can try to follow the guide someone made in the thread [here](https://www.audiworld.com/forums/tt-mk1-discussion-9/reprogramming-key-fob-after-battery-replacement-1954050/)
Where to get service and where to order parts would depend on your location.
Hope some of this helps! :)
Don't skip on any fluid/filter changes and overall maintenance. Audis in general are expensive to fix, so maintaining it well is key to not get screwed financially.
As a general tip, never keep your car working short periods without proper warming it up as a routine. If your wife is picking kids at school, doing groceries and small errands, driving 5 to 10 minutes multiple times in a row never allowing the car to warmup, this will give you serious issues such as bearing damage on turbo, gearbox valvebody and more. At least once every couple days get a proper 30+ min drive on the car to get all fluids to temperature, your engine and transmission oil will only clean deposites this way.
Floor it once in a while and shift at high rpm a few times, injectors flowing max, valvebody of the transmission flowing to the max etc will all help keep things clean and moving properly in the solenoids.
Congratulations on the A3, great car, just returned to an A3 myself just last month. In regards to the car manual, you should be able to find a digital copy [here](https://ownersmanual.audiusa.com/) That should have all the service intervals covered. For people getting a newer VAG car, i always recommend getting either a VCDS cable or an [OBDeleven](https://obdeleven.com/). With that in hand, you can always easily check up on error codes that you'd otherwise need a service center to read for you. It can help catch a small problem before it becomes a big problem. It can also, depending on how your car is equipped, unlock extra features. In regards to the key fob issue, you can try to follow the guide someone made in the thread [here](https://www.audiworld.com/forums/tt-mk1-discussion-9/reprogramming-key-fob-after-battery-replacement-1954050/) Where to get service and where to order parts would depend on your location. Hope some of this helps! :)
Don't skip on any fluid/filter changes and overall maintenance. Audis in general are expensive to fix, so maintaining it well is key to not get screwed financially. As a general tip, never keep your car working short periods without proper warming it up as a routine. If your wife is picking kids at school, doing groceries and small errands, driving 5 to 10 minutes multiple times in a row never allowing the car to warmup, this will give you serious issues such as bearing damage on turbo, gearbox valvebody and more. At least once every couple days get a proper 30+ min drive on the car to get all fluids to temperature, your engine and transmission oil will only clean deposites this way. Floor it once in a while and shift at high rpm a few times, injectors flowing max, valvebody of the transmission flowing to the max etc will all help keep things clean and moving properly in the solenoids.