virtualbox guest additions problem, ububtu-17.04

[Stuart McGraw]

Hello, 

I am a new Ubuntu user or at least I want to be but am
hitting a major install roadblock.  I am installing 
Ubuntu-17.04 as a VirtualBox guest and need to install 
the VirtualBox guest additions.

The instructions I've seen on the internet are all over 
the place in terms of what needs to be done.

There are a bunch of virtualbox* packages in the Ubuntu
repository and its not clear which if any I need to 
install.

FWIW I have tried installing virtualbox-guest-x11 
but on reboot, the system is trashed -- the window
remains black, changes size a few times, then the VM
hangs.

Does anyone here have, or can point to, a clear 
authoritative set of instructions to get this working?

(FWIW, on do-it-yourself, techie, complicated Arch
Linux this was trivial.)

(Host system is Fedora-23, VB-5.1.10 if that matters.)

Thanks...