the installation file is currently on my PC which i downloaded from Dynatrace's site, it's not on a DVD. i tried to locate the last upgrade file on the AMD when we upgraded from 12.0 to 12.2 last year, so i can just overwrite that file with the new one, but could not locate it.
I typically use either 'scp' (on linux) or 'winscp' (Windows) to copy the installer file to /tmp/ on the AMD. the installer is only needed during the install/upgrade process, so /tmp/ is as suitable a location as any.
There's no requirement for it to be located anywhere specific, as Ulf says anywhere you can write it to is fine. Some particualrly heavily locked down linux installs may place executable restrictions (noexec flag) on certain mount points, but a AMD built with the Dynatrace provided kickstart file does not.