From the main page of Clove, select your hub and visit the "Connections" page. On this page, you will see a section for "Salesforce" that tells you whether you are connected or not.
If you are not connected, simply click "Connect to Salesforce" in order to go through the authorization flow. Once done, you'll be taken back to Clove and you will see that the connection status has changed.
Clove will not pull down any content from Salesforce unless you activate the modules that you want to include. Visit the "Modules" page for your hub and enable the particular modules that you want your hub to use.
Salesforce has requirements on which editions can access the API. This is not a Clove-specific limitation, so we aren't able to work around it.
As of this article, the following editions are able to use Clove's Salesforce Connector: Enterprise, Unlimited, Performance, Professional with Data Add-On.