Once Evercontact is activated on your organization's Salesforce, you'll have a tab where you can pair Evercontact with Salesforce by adding your email as you see below.

You'll then be invited to provide gmail and salesforce permissions as you see below:

Finally, you confirm the pairing on this screen and then you're all set!

 You can only do this once your domain admin has added Evercontact on the Appexchange.  Feel free to reach out to us at anytime to move forward with that as there's a 10 minute setup to be done (pro, group, enterprise versions) and your domain schedule a walkthrough, or follow the docs on the Appexchange.