Hi 

I don't know if you managed to get the answer to your question.

Here's the video that helped me: https://www.youtube.com/watch?v=VQJodqSE5DM

If I start an email with 

Hi Valued Customer,

First, I create a field called "First Name" using Studio.  The studio field is then x_studio_first_name.  

If in the Contacts, the person's first name is John.

Then the code behind is:

Hi Valued Customer, ,

And the results should be

Hi John,