Step 1: Update System

$ sudo dnf update
$ sudo reboot
(So any new installed kernel will be loaded)

$ sudo dnf install gcc kernel-devel kernel-headers make bzip2 perl

Go to the VirtualBox Menu > Devices > Insert Guest Additions CD image

Automated:
Press Run

Manual:
$ cd /run/media/$USER/VBox_GAs_*/   # Adjust path if needed
$ sudo ./VBoxLinuxAdditions.run

$ sudo reboot

Verification:
$ lsmod | grep vbox
(Check to see if vboxguest is listed)