This code will limit contact creation to only email address match when a chat session is initiated via Embedded Service (formerly snap-in) with Salesforce chat.
My company does not have a Salesforce developer on staff, so as the Admin, I'm looking for some guidance as to where to insert the code recommended in this solution. 

Hello,   I need to archive (remove from salesforce) around 400.000 email messages. I tried the weekly export but files are too big and it's not possible to open them (in case I need to import some information back to salesforce). The main issue is that the email message body is not stored in one cell (one single email message is scattered in several rows). The same happens with Data Loader.  Does anyone ever try this? What are my options? I'm running out of space and I really need to free up some space...