Registrating+insurance for foreign car in DE FFM (Frankfurt)

Hello!
Hello!

I am bringing my car (from Slovenia, also EU Member : Protected content Germany and since my insurance and everything runns up in september I want to do everything here. Does anyone have tips recomendations in what order and where is the best to do everything (technical inspection, exaust measurment, insurance (the cheapest version) zulassung and so on. The main thing is to keep the price for everything as low as possible.

Thanks in advance!