Download and install Enterprise Edition. Please read this guide for more details on how to install Enterprise Edition to your Windows machine.
When Enterprise Edition is installed, go to the
C:\Program Files (x86)\Ascensio System SIA\ONLYOFFICE Community Edition\CommunityServer folder, where the following two folders are located:
Copy these folders and paste them to the
C:\Program Files (x86)\Ascensio System SIA\CommunityServer folder.
By default, Enterprise Edition uses the same database as Community Edition, therefore you do not need to restore the database backup if you install Enterprise Edition on the same server. If you install Enterprise Edition to a different machine, just transfer the backed up folders with portal data and MySQL database to the corresponding directories on the new server.
Now you can launch the portal and check it for correct work and all data presence. The last thing you need to do is to go to the Payments page and upload your license key. To find out how to buy a license key, you can refer to this article.