How to add a gui to RHEL 7.4

Hello,

I don't know much linux but I need to get a RHEL7 server up and running and have been struggling with it for days. I've followed other threads from here but each issue leads to another issue and the whole thing is becoming soul destroying.

All I want to do is setup a RHEL7 server with a GUI on a VM. It won't be a production box so we're not buying it, simply a test machine for a tool which collects information from the server.

I've got as far as having the command line based OS working but the rest of it just won't happen,

I started with this thread:

https://access.redhat.com/solutions/5238#res_a

When I do

yum repolist

I get Loaded plugins: product-id, search-disabled-repos, subscription-manager. Then I get This system is not registered with an entitlement server. You can use subscription-manager to register. Then repolist:0

So next I try

yum groupinstall gnome-desktop x11 fonts

And as expected "there are no enabled repos"

So that gets me to this thread: https://linuxconfig.org/rhel-7-solution-to-there-are-no-enabled-repos-message

I successfully did these:

[root@rhel7 ~]# mkdir /media/rhel7-repo-iso
[root@rhel7 ~]# mount /dev/cdrom /media/rhel7-repo-iso/
mount: /dev/sr0 is write-protected, mounting read-only

When I try this

vi /etc/yum.repos.d/RHEL_7_Disc.repo

I get a screen full of squiggles and I have no idea what to do with it ! I eventually managed to find :q! !!!!

[root@rhel7 ~]# vi /etc/yum.repos.d/RHEL_7_Disc.repo
[root@rhel7 ~]# cat /etc/yum.repos.d/RHEL_7_Disc.repo
[RHEL_7_Disc]
name=RHEL_7_x86_64_Disc
baseurl="file:///media/rhel7-repo-iso/"
gpgcheck=0

So I tried ignoring the cat line since thats just trying to put out a file that doesn't exist. Instead I tried typing starting at [RHEL_7_Disc] but when I type a square bracket in vi it comes up with a square blob !! OMG help !!

I also tried using rhn_register. That tells me that my SSL certificate does not exist, and of course being someone that doesn't even know how to use vi my chances of successfully fixing that one are also pretty slim.

I'm amazed that an enterprise grade product like this doesn't install the GUI with relative ease out of the box but whatever the reasons behind that are please help me get it setup !! thanks