Hectors instruction list works great, but if any modules are added then you have to recompile the kernel by going thru the nano editing of the virtualbox.conf file and checking that all the module names that it showed are in there.
It looks like you have to manually edit that file to include all of the module names, and then it will recompile the kernel and redo all of the modules to get things working.
If you display the terminal you should see it clean the build area, and recompile all the modules for virtualbox
and then dkms will autoinstall at that point.
This to me is a problem that should be addressed when the updates come along.
Once you have the initial part done then PKGBUILD should contain whatever steps are needed to update it.
The more you look at these problems the more you begin to understand how things work in Linux period.
So like the rest of the world, I am hoping that Package Manager will someday allow automated processing of .DEB files so that we don’t need to rely on everyone trying to figure it out.
The VirtualBox engine goes out and checks oracles site for updates, However they do not offer updates for ARCH linux for you to download. So you are best to get them via the updater or software manager or Pacman or whatever you use to obtain software. It seems to boil down to ARCH and Antergos and other ARCH based Linux, do not have package builds that you can download via your web browser. Its more that they are written for other types of linux that accept .deb and .rpm generic formats.
Now please dont smack down, but I agree that they need to encourage ARCH based linux to have things maintained, to keep up with the rest of the world.
I understand that keeping up with the world of software, is a task that is nearly impossible.