Using zDoom Launcher
Using
the zDoom Launcher once it's configured is a breeze. As long as
you use relative paths in your configurations, you can use it from a
portable device as well. All you have to do is select the game
you want and click on the lost soul (the flaming skull on the
right). This will launch the game with the settings specified in
the configuration file for the one selected.
You'll also
notice below that there is a long text box on the bottom. This is
left for additional parameters. Say you want to play a specific
wad file but want to do it with looney toons sprites. No
problem. Just select the item to play and add the wadfile
parameter in the bottom box as you would from the command line.
An example would be "-file extra\looneytunes.wad.".

You
can also use the same box above to add parameters for multi
player. You may use "-host 3 -warp 1 -skill 2" to host a game or
something like "-join 168.23.1.56" to join the game. If your
regularly join or host with the same specific numbers, you can set
these in another configuration file to keep from having to type it each
time. Just add them to the parameters already in the
configuration.

You can select the items by clicking or cycling through the items.

You'll
also notice that there's an entry "Duke Nukem 3D" above. Yes,
this is correct. Duke 3D is not a Doom TC but the actual windows
port of Duke Nukem 3D. This launcher was programmed with zDoom in
mind, but can be used with properly set configuration files as a
generic game launcher. You can even change the title by typing
"SetTitle" in the bottom text bar, then a space, then the title you
want. When you move away from the text box, it will save the
title and advise you of this. The title is stored in "Title.cfg"
in the same directory as the zDoomLauncher.exe. You could even
use this to launch e-mail clients, media players, or anything else you
want to set up a configuration file for.
If something
keeps going weird with the item you are launching and you want to see
what parameters are actually being passed. Simply select the
title you want, then type "Show Parameters" (case sensitive) in the
bottom text bar, then click the launch button. Instead of
launching the title, it will show the program, parameters, and starting
location being passed in the big info window. This is helpful if
you seem to have a corrupt configuration file and possibly need to fix
it.
You can also minimize zDoom Launcher by using the
little down arrow. There is an X by it to close the launcher (not
shown in these pictures). All items have tool tip text if you
rest the cursor over it. When you minimize, it does not go to the
task bar but instead is a small movable bar on your desktop. You
just have to double click on the bar to restore it. This is shown
in the picture below. It was done this way to allow multiple
launchers to be kept available without cluttering up the task
bar. Notice the multiple titles in the picture below.

One
of them is for my Doom based games while the other is for the other
games I have (though I don't really know if there are any other real
games out there that can compare).