You don’t have to mount CD’s, Zip disks, etc, manually. Let the BeOS do it for you!
Right-click on the Desktop and select ‚Settings…‘ from the ‚Mount‘ submenu.
Now, in the ‚Disk Mount Settings‘ window, select ‚All Disks‘ in the ‚Automatic Disk Mounting‘.
You can set options for what disks to mount during boot as well, if you want only your BeOS volumes to show up, or if you want HFS (Mac), FAT16/32, NTFS or Linux partitions as well.
If you want to get more selective about it, see the tip Selective volume mounting.