Delete Old Time Machine Backups to Recover Space

I am trying to delete old backups on my synology NAS. Any help woud be great, I did try to test on a Thumb drive and still no luck.

steps

1. tmutil listbackups
2. sudo tmutil delete
3. sudo tmutil delete "snap shot"

Got this error:

Specify either a path or a mountpoint and timestamp

Usage: tmutil delete [-d backup_mount_point -t timestamp] [-p path]

admin@Brians-Macbook-Pro-M2 ~ %