CRM connectors for ACS are still under development. Given this limitation, you have two options
Export the data from Salesforce via Flat files and place it on Campaign sFTP. Later you can have workflows in ACS to import this data.
Purchase Campaign Prime Connector after talking to Sales. In this feature you will be provisioned an ACC instance along with your existing ACS along with a connector between the two. So, ACC can be used to connect with Salesforce in real time and import the data in ACC database. Then through Prime Connector you can move the business data in ACS database and use it there.