Manual file management is reserved for advanced modders who own the DLC and are migrating backups. If you do not own the DLC, no sketchy Reddit link or YouTube video description will give you a clean, working, safe copy.
Approximately 8 GB. If a website offers a Fallout 4 DLC files download that is 500 MB total, you are being scammed. Fallout 4 Dlc Files Download
When you complete a Fallout 4 DLC files download via backup, look for these exact names: Manual file management is reserved for advanced modders