Before you start using SharePoint Security Sync solution, it is necessary to enable server-based SharePoint integration for your Dynamics 365 CRM environment.
To do this, follow the steps given below:
Navigate to Advanced Settings --> Settings --> Document Management.
Go to ‘Enable Sever-Based SharePoint Integration’.
Click on Next.
Now, select the location of SharePoint site and click on Next.
Now, enter the URL of SharePoint site that you want to use --> Click on Next.
Once the site is validated, click on Finish.
The server-based integration of SharePoint site is now enabled for your Dynamics 365 CRM environment. Now, go back to Settings --> Document Management Settings.
Select the Entities for which Document Management needs to be enabled --> Enter the URL of active SharePoint sites where you want to store documents --> Click on Next.
Check ‘Based on entity’ to automatically create document libraries and folders that are based on the Dynamics 365 Account on the SharePoint site. Users will not be prompted to create them. If you don't want folders automatically created, do not select the ‘Based on entity’ check box. Click on Next button.
Click on Finish.
Once this is done, you can easily store Documents/Attachments related to selected Entities in the respective SharePoint site using Attach2Dynamics button.