Example of a desktop file starting virtual machine called w7 is as follows (file name w7.desktop) These files can be created manually, but also using Virtual Box GUI. Once we have these files, it is enough just to copy them into /.local/share/applications and they will be e immediately available in the gnomes activities. From the we can just drop and drag them to dash. If we want to create them manually, we can use the example from the above. The ids of the virtual machines can be obtained using the following
vboxmanage list vms
"w7" {25e911a6-7bae-422a-84c2-30ced68d701d}