There's some info here (in German):
SchulbeginnQUOTE
Das Schulamt informiert Eltern mit schulpflichtigen Kindern automatisch, wann und wo sie ihr Kind anmelden müssen.
Die Schulanmeldung findet in der Regel bei der Schule statt, in deren Einzugsgebiet das Kind wohnt.
The school board will let parents know automatically, where and when to register your child for school. Registration will usually be at the school nearest your home.
You'll need to buy a backpack, and a whole list of school supplies - the school will give you a list, either before school begins or during the first few days. All first graders are given a 'Schultüte' by their parents on the first day of school, full of goodies and little stuffed animals and such - don't let your kid be the only one without one! Whether or not there are school buses depends on your area and how spread out it is. There aren't many. Kids usually walk or their parents drive them. Again, English lessons depend on the school, but generally don't start until like 6th grade if I remember correctly.