Optimizely (formerly Episerver) CMS 12 comes with lots of exciting new stuff, including .NET 5 support (thank you finally!).

Setting up a new website in a development environment is easy (Clone the .NET 5 preview repo here), however when you want a shared file share for the blobs (instead of the local App_Data folder), it's a little bit hard to find the accurate documentation for it.

To configure an Optimizely CSM 12 (preview) website to use a file share, you need to edit the appSettings.json file to include BlogProviderOptions, like this:

{
  "EPiServer":{
     "Cms":{
            "BlobProvidersOptions": {
                "DefaultProvider": "fileShare",
                "Providers": {
                    "fileShare": "EPiServer.Framework.Blobs.FileBlobProvider, EPiServer.Framework"
                },
             } 
             "FileBlobProvider":{
                 "Path": "\\dbserver\blobs"
             }
     }
  }
}

Until you do so, the App_Data folder will be used for your CMS content files.

The documentation for this can be found under the Deploying to Windows Servers section.