How are paths to files and folders constructed in OS X?
Solution 1:
There's no disk letter in OS X unlike Windows.
The mount point for disks is usually /Volumes. For example, files on a flash drive with the name FLASHDRIVE will be located in /Volumes/FLASHDRIVE/.
The startup disk is the root, /. Therefore, the Users folder is /Users. No drive letter is prepended to this.
Solution 2:
You can right click the file and "Get Info". The path is written right there. Alternatively you could e.g. drag the file into a terminal window to see the path..