There are differences from school to school but some general info I can provide:

• All kids start in elementary school. For kids with special needs are either inclusive classes or special needs schools.
• After elementary school they can continue with Haupt- / Realschule or Gymnasium
• First class usually starts at 7:30 - 8:00, sometimes this slot is free and they start with the second block, one block takes 45 minutes
• We usually had a break for breakfast (around 10:xx) and the morning block ended around 12:xx, afternoon block usually started around 14:xx
• The exact starting times may differ from school to school

In elementary school the topics are more of less the same for everyone:

• German (focus on reading, spelling and basic grammar)
• Mathematics
• English (not sure if this is default now, but my niblings learned the basics in elementary school)
• Something nature / environment related
• Sports
• Music
• Religion (which one depends on the area, we had Roman Catholic and Evangelical Religion)

There may be additional options depending on the school and area. E.g. my oldest niece has a class for gifted children where they learned more digital stuff, she build her own very simple computer game where she also had to create the images and sounds. But this is not default.

After elementary school the classes depend on the type of school. Hauptschule had a very strong focus on crafting like woodworking and less focus on theoretical stuff while at Gymnasium they have to choose at least one additional language (Latin is an option) and focus more on “book stuff”.

As a pupil you can also still go for a higher graduation level after getting the previous one. E.g. of you finish Hauptschule you can do your 9+1 (this refers to the 9. grade after which you finish Hauptschule +1 year for Realschule which you finish after 10. grade). And after that you can also go on and do your a-level or get the qualifications to study at a Fachhochschule or similar schools and get a degree.

Edit: forgot to add that no matter which school a child visits after 4. grade they’ll learn basics of natural science (chemistry, physics and biology) but the topics and depth differ depending on the school. Additional languages (besides German and English, which is default for everyone) are often not available on Hauptschule, on Realschule we were allowed to choose between a third language (French or Italian), crafts and home economics.

At 11. grade and later I was able to opt out of Religion and go to Ethics instead. Some schools offer this as an alternative, otherwise parents can opt out if religions classes afaik.