Help with new feature - wix-crm-backend > getContactById()

I have created a Wix site using only drag an drop but need to use a small amount of Wix code.
I have stored a unique external website URL in each users CRM contact info and when the user is logged in use this URL to embed the external site in a Wix web page. I have figured out the Wix code so far to extract the logged in userid, and to load an external webpage based on the value of a string variable. Past forum posts suggested that to get specific data for a user it would need to be stored in a separate database. However I see a new feature released on the 20 Feb 2019 might provide me with access to the data I need. Unfortunately the example code for getContactById() only shows how to create a new contact and not how I might pass in the userid value and get back ContactInfo type data. I managed to work out how to Wix code using example code and experimenting line by line to see what it does, but with this function being so new I assume this is why there are no examples out there yet.