After releasing the early versions of exposure notification API to developers last week, Apple and Google have shared guidelines and released sample user interface designs that developers working on authorized contact tracing apps can use to better implement the API.
Alongside the images, both of the companies have shared sample code intended for developers to ensure that user privacy is not compromised. If you are interested, you may take a look at the sample code released by Google on GitHub.
Also, both the companies say contact tracing apps must not access or even seek permission to Location Services. Existing apps from public health authorities that use location permission will not be given access to the new API.