VboxLinuxAdditions and Debian 11 - how to make friends without driving yourself crazy?

Question

Debian

Hello. Everyone has already eaten this question, but why is it always so dreary with them?
I have almost every time one problem pops up, then another.
Is there a proven sequence of steps to get started on Debian 11? On the tenth a couple of months ago, somehow without questions through mounting and a simple launch, everything was resolved, but on 11 - again problems, writes unable to locate package virtualbox-guest, although everything seems to be mounted.

Answer 1

Something is not clear somehow.
Can't you install add-ons?
Connect the disk with additions, mount it in the virtual OS, then install with the command (the paths may differ, the package names too, plus I don’t remember exactly which extension of the package, but one of the two):

run /media/<ПУТЬ К ДИСКУ>/vboxadditionslinux64.run
sh /media/<ПУТЬ К ДИСКУ>/vboxadditionslinux64.sh