CRM Bitrix24 box. How to add files and folders to Contacts?

Question

Bitrix24

There is a boxed version of Bitrix24.
You need to add the ability to attach files and folders to Contacts.
Ideally, the Contact should display an additional tab. When the tab is opened, a personal folder (Contact ID) will be created and the Bitrix.Disk interface will be loaded, for which this folder will be the root.
Addition:
- the interface for working with files should be on a separate tab
- working with files should be in the form of the Bitrix.Disk interface
- two-way synchronization with a third-party server must be configured. Files that will be stored in the Bitrix.Disk storage (files and folders of Clients) will be automatically synchronized with another server via sftp. If the files are changed, added or deleted on another server, they are also changed on the Bitrix24 server.
Added application tab. Set up a connection to the server. Files and folders are synchronized. It remains only to pull the Bitrix.Disk interface onto my application.