In order to retrieve data from any of the Dutch Healthcare institutes you have to navigate to external services.
After that the patient should be able to find the right healthcare institute.
After this step the patient has to login using DigID, so there is no way any developer could test this.
In the next screen you will be able to select the right service that you would like to receive data from.
This is of course according to the Dutch ZIB Huisartsgegevens 1.0, in this case it is showing the list of episodes at one single GP.
Another query is to retrieve the entire Journal from he doctor (GP).