dbus-daemon[841]: [session uid=999 pid=841] Activating service name='org.gtk.vfs.Daemon' requested by ':1.0' (uid=999 pid=842 comm="" label="unconfined")
dbus-daemon[841]: [session uid=999 pid=841] Successfully activated service 'org.gtk.vfs.Daemon'
dbus-daemon[841]: [session uid=999 pid=841] Activating service name='org.gtk.vfs.Metadata' requested by ':1.0' (uid=999 pid=842 comm="" label="unconfined")
fuse: device not found, try 'modprobe fuse' first
dbus-daemon[841]: [session uid=999 pid=841] Successfully activated service 'org.gtk.vfs.Metadata'
A connection to the bus can't be made
Using CD-ROM mount point /cdrom/
Identifying... [431d88f14d0e95e508b0a488d8fe2364-2]
Scanning disc for index files...
Found 4 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
Found label 'Ubuntu-Studio 18.10 _Cosmic Cuttlefish_ - Release amd64 (20181017.2)'
This disc is called: 
'Ubuntu-Studio 18.10 _Cosmic Cuttlefish_ - Release amd64 (20181017.2)'
Copying package lists...gpgv: Signature made Wed Oct 17 22:53:51 2018 UTC
gpgv:                using RSA key D94AA3F0EFE21092
gpgv: key D94AA3F0EFE21092 was created 1208 days in the future (time warp or clock problem)
gpgv: key D94AA3F0EFE21092 was created 1208 days in the future (time warp or clock problem)
gpgv: key D94AA3F0EFE21092 was created 1208 days in the future (time warp or clock problem)
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-Studio 18.10 _Cosmic Cuttlefish_ - Release amd64 (20181017.2)]/ cosmic main multiverse restricted universe
Repeat this process for the rest of the CDs in your set.