The Folk + Zapier Connector is a bit limited, but should cover most of your basic needs, like adding new contacts to the CRM.
You'll need your Folk API key in order to enable to connect Folk to Zapier.
There's quite a few limitations in Folk's Zapier connector (like no trigger functionality and minimal custom field support), and they don't yet have a Dev API or plans on further updating their connector, so your hands are a bit tied with what's currently available.
Once they release their Dev API, you'll be able to use the Webhook functionality of Zapier to create custom actions.
(This is a more technical feature that requires API knowledge)