to what what does mount point refer in the tmutil man pages

I am attempting to associate a new drive with existing backups. The command is supposed to be something like

sudo tmutil associatedisk [-a] "/Volumes/iMac_HD" "/Volumes/TC4TB-1/Backups.backupdb/Chuck's iMac/Latest/iMac_HD"

Where cd Volumes/iMac_HD places you at the rood of the drive to be backed up

and cd /Volumes/iMac_HD" "/Volumes/TC4TB-1/Backups.backupdb/Chuck's iMac/Latest/iMac_HD" places at the root of the previous drive's backup.

I get the following response after providing my password.

Usage: tmutil associatedisk [-a] mount_point volume_backup_directory

A local volume mount point and a snapshot volume path are required.

I feel I must be misunderstanding the term mount_point or volume_backup_directory

Thank you