[CentOS] CentOS 7/GNOME 3 customise top panel

Hi,

Is there any way to customise the top panel in CentOS 7 with GNOME 3 
(which I recently tried for the first time)? Specifically, I want to add 
"application launchers", as it will make start-up faster than the 
standard alternatives. (Because you can move the mouse directly to the 
right place - you don't have to carry out another action, wait for icons 
or menu items to pop up, look for the right one etc first.)

People on the web talk about a "context" menu that opens if you use some 
kind of weird combination of right mouse-click and Alt, Windows key, 
Ctrl, left click, Alt Gr or whatever, but there seems to be no way to 
make that happen on CentOS.

I found an answer of sorts in 
https://www.centos.org/forums/viewtopic.php?t=47957 -
> In straight Gnome Shell -- CentOS 7 defaults to a modified version 
> using extensions -- the panel *is* locked. Visit extensions.gnome.org 
> to see if something there is useful.
- but I don't think I quite understand it. I mean, the ability to add 
extensions is nice, but if the panel is locked, isn't an "unlock" 
function what I should be looking for? This doesn't quite sound like an 
"extension". Or is the actual menu everyone talks about itself an 
extension? If that's the case, surely isn't there some other way to make 
the changes? If the standard panel allows stuff to be added, there must 
be a standard way to do it, right?

Also, if I do need extensions, I'd prefer to install it via the package 
manager system rather than through a special web interface...

Does anyone know more about this? Any help would be appreciated. - 
Except, that is, I don't really need anyone to suggest switching to MAME 
or some other alternative desktop. I might end up doing just that, but 
it really bugs me that I can't get functionality that's supposed to be 
there to work...

- Toralf