When the doctor or nurse takes your vital signs they will be checking things that you probably have had checked by other doctors, like:

Taking your temperature.

Taking your blood pressure.   A nurse or doctor will wrap a piece of fabric (a cuff) around your arm, and pump air into it. It will get tight on your arm. Then, they will slowly let the air out.  At the same time, they will listen to sounds coming from inside your arm. They will use a thing called a stethoscope to hear the blood pumping in your arm. This will tell them what your blood pressure is. This only takes a few minutes.