I hope you'll never get sick when you're travelling in Germany, but we're going to the doctor today, ok? First, you might make a call to get an appointment. With an appointment, you don't have to wait too long to see the doctor. So you call the „Praxis“, that's what the doctor's office is called, „Praxis“, and tell the Sprechstundenhilfe, that's the woman answering the phone: „Ich möchte einen Termin vereinbaren.“ Or a little less polite: „Ich brauche einen Termin“, meaning: I need a doctor's appointment. The woman might ask you: „Worum geht es denn?“, meaning: What's this about? And you can tell her: „Ich habe Halsweh“, or „Ich habe Kopfweh“. You see: the syllable „weh“ means pain in this case. So you tell them where it's hurting you. Der Hals is the throat, der Kopf is the head, der Bauch is the stomach.
When you have your apointment, you try to be there on time. When you enter the Praxis, you go to the counter and tell them your name. You say: „Guten Tag. Mein Name ist Miller. Ich habe einen Termin um drei Uhr.“ That means: „Hello, my name is Miller, I have an apointment at three o'clock.“ The woman then might ask for your insurance card, „Ihre Versichertenkarte bitte“. After everything is checked, she will tell you: „Gehen Sie schonmal vor ins Wartezimmer.“ The „Wartezimmer“ is the waiting room. When you enter it you can say „Guten Tag“ to the other patients waiting there. The doctor will call you into his Arztzimmer, the doctor's office. Usually he comes into the waiting room (or sends his assistant), saying either your name or simply „Der nächste bitte!“ meaning: Next one, please.
You tell him where it hurts – if you don't know how to say it, just show him with your hands. Maybe he says: „Machen Sie sich bitte frei.“ This is hard to understand, isn't it? It means: Get undressed. Ususally just the upper part of your body. When he's done examining your body, he will say: „Ich gebe Ihnen ein Rezept.“ The „Rezept“ is a piece of paper. With this, you go to the next pharmacy to get your medicine. Maybe the doc will also say: „Gute Besserung!“ meaning: Get well, soon!