You don’t.
Instead of storing files in SQL Server, which is a horrible idea, instead, store them in Azure Blob Storage, an AWS S3 bucket, your web server, or a file server. Anywhere but the SQL Server.
If you have some 3rd party application that absolutely must store the files in the database, configure the table that it’s using for FILESTREAM.
If you are going to restore a database with FILESTREAM data Joey has some warnings on the restore.
Denny