Follow the instructions below to enable Email Experiences' Salesforce Integration.
As a best practice Terminus recommends using an API user within SFDC to install the managed package. This will prevent the need to reinstall should the installation user be removed from SFDC in the future.
One important thing to note, the user in Email Experiences who authenticates the SFDC integration must match the SFDC user who installs the managed package.
Install Email Experiences to your Salesforce instance via the Managed Package.
Navigate to your Account Settings > Integrations : CRMs
Under CRM options, click the Connect button under Salesforce.
Log into your Salesforce account and click Allow.