dbus-daemon[788]: [session uid=999 pid=788] Activating service name='org.gtk.vfs.Daemon' requested by ':1.0' (uid=999 pid=789 comm="" label="unconfined")
dbus-daemon[788]: [session uid=999 pid=788] Successfully activated service 'org.gtk.vfs.Daemon'
dbus-daemon[788]: [session uid=999 pid=788] Activating service name='org.gtk.vfs.Metadata' requested by ':1.0' (uid=999 pid=789 comm="" label="unconfined")
fuse: device not found, try 'modprobe fuse' first
dbus-daemon[788]: [session uid=999 pid=788] Successfully activated service 'org.gtk.vfs.Metadata'
A connection to the bus can't be made
Using CD-ROM mount point /cdrom/
Identifying... [b1dbde5c00fbebaafc31b34ab2f25c86-2]
Scanning disc for index files...
Found 2 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
Found label 'Ubuntu 18.10 _Cosmic Cuttlefish_ - Beta amd64 (20181005)'
This disc is called: 
'Ubuntu 18.10 _Cosmic Cuttlefish_ - Beta amd64 (20181005)'
Copying package lists...gpgv: Signature made Fri Oct  5 08:04:07 2018 UTC
gpgv:                using RSA key D94AA3F0EFE21092
gpgv: Good signature from "Ubuntu CD Image Automatic Signing Key (2012) <cdimage@ubuntu.com>"

Reading Package Indexes... 0%

Reading Package Indexes... Done
Writing new source list
Source list entries for this disc are:
deb cdrom:[Ubuntu 18.10 _Cosmic Cuttlefish_ - Beta amd64 (20181005)]/ cosmic main restricted
Repeat this process for the rest of the CDs in your set.