To use Online Contract Collaboration with CLM (Contract for Salesforce) in Salesforce Classic, additional setup steps are required. Below are the steps needed for both Contract Agreement and custom objects.

Contract Agreement Object

To launch and use Online Contract Collaboration with Salesforce Classic with the Contract Agreement object, take the following steps:

  1. From CLM (Contracts for Salesforce), navigate to the Contract you want to display the Document Action option to launch and use Online Contract Collaboration. 
  2. Click Edit Layout
  3. In the Contract Agreement Layout panel, select Visualforce Pages.
  4. Click +Section and drag it down onto your page layout below the Custom Links section.
  5. Name the new section, and select 1 Column. 
  6. In the Contract Agreement Layout panel, drag the OCC Document View Classic Visualforce Page into the new section you added to the page layout. 
  7. Click the wrench icon in the upper right hand corner of the new section. 
  8. In the Visualforce Page Properties window, check the Show Scrollbars option. 
  9. Click OK
  10. In the Contract Agreement Layout panel, click Save

Custom Object 

To launch and use Online Contract Collaboration with Salesforce Classic with a custom object, take the following steps:

  1. In Salesforce Classic, click Setup.
  2. Under Quick Find, search for Visualforce Pages and click the Visualforce Pages link.
  3. Under Visualforce Pages, locate and click OCC Document View Classic
  4. Copy the code under the Visualforce Markup tab.
  5.  Under Quick Find, search for Visualforce Pages and click the Visualforce Pages link.
  6. Under Visualforce Pages, click New.
  7. Enter a Label and Name for the object you want to use, and paste the code you copied into the Visualforce Markup tab. 
  8. Change the standardController="Contract_Agreement__c" to the API name of the object you want to use. For example, if you want to use the Contract object, change the code to standardController="Contract".
  9. Change the !Contract_Agreement__c.id to the API name of the object you want to use. 
  10. Click Save.
  11. From CLM (Contracts for Salesforce), navigate to the Contract you want to display the Document Action option to launch and use Online Contract Collaboration. 
  12. Click Edit Layout
  13. In the Contract Agreement Layout panel, select Visualforce Pages.
  14. Click +Section and drag it down onto your page layout below the Custom Links section.
  15. Name the new section, and select 1 Column
  16. In the Contract Agreement Layout panel, drag the Visualforce Page you created into the new section you added to the page layout. 
  17. Click the wrench icon in the upper right hand corner of the new section. 
  18. In the Visualforce Page Properties window, check the Show Scrollbars option. 
  19. Click OK
  20. In the Contract Agreement Layout panel, click Save