Some "patients" are taken to "care-places", not because they are injured, but simply because they need to be looked after. Such care-locations can include schools, fire-stations, and similar places. You just need to have every type of POI implemented in your Control-Center or neighboring Control-Centers. As has often been mentioned, it's worth reading the Wiki - so far, it has all the answers to your questions.

Well, not every tag is needed (like harbor, airport, castle or camping and some more). Yet, there are several that are connected to calls although they are not the actual scene.

And yes, please use the tutorial, IW. We're always in when help is needed but we cannot explain every single element of the game. You might also collect questions instead of starting new threads for every topic.

Du bist herzlich eingeladen ihm jedsen einzelnen POI aufzuzählen! Aber um mich deiner Art anzuschließen und meinen "Klugscheißermodus" ebenfalls zu aktivieren: Doch, um das volle Einsatzspektrum der Sim abzubilden und keinen potentiell generierten Einsatz zu verpassen, ist jeder einzelne POI nötig!

I'm not sure what a KTW/RTW detector is supposed to be.
If I understand the question correctly, maybe thus helps:

KTW: BLS unit, equipped for planned patient transports or "simple" emergencies like an ark fracture wothout severe pain. Or as a first responder.
RTW: ALS unit, equipped for all and staffed for most kinds of emergency.
NEF: ALS+ unit. Brings a physician to a RTW for i.e. advanced airway management, resuccitations or when a patient is so bad that they are expected to crash or when more medication is required than the RTW can/may apply. The latter may differ from county to county.

You can translate it to: code 3 (RTW-Melder) and without code 3 (KTW-Melder)

As Leitessen said. RTW-Melder = lights an sirens, KTW-Melder = no lights an sirens.

"Melder" by the way means pager in this case and which address (in this very old case it's the 5 numbers that translate into sounds that fire up the pager over the analog radio net). In Germany all ambulance crews have unit specific pagers by which they are called for a job.

Und du meinst jetzt echt, dass es zielführend ist, wenn wir uns deshalb gegenseitig ans Bein pinkeln?

Da du offenbar meinen Gedanken dahinter suchst, erläutere ich es gern kurz: Wenn man deine Aussage so hätte stehen lassen, wäre garantiert in wenigen Tagen ein Beitrag gekommen, dass es gewisse Sachen in seiner Region nicht gibt und wie er damit verfahren soll (Einsatzspektrum hin wie her). Dem wollte ich vorbeugen - mehr nicht. Da kann man einen wohlgemeinten Nachtrag auch mal unkommentiert lassen, statt latent Streit zu suchen (grad als Admin).