Not exactly:
with the launchy version as it is, you will download the file (after choosing
the destination folder). When downloaded, vlc will start and read the
video.When you close vlc, the video will be deleted. That's what those 4
lines mean (roughly). The first one is to put first to make it a script.
#!/bin/bash
cd ~/tmptube
youtube-dl $1
vlc *.*
rm ~/tmptube/*.*
Oh, you also need to create a folder in your user folder named tmptube if you
use the script unmodified.
If you want to understand that stuff better, check some introductions to bash
scripting.
And to using the command line.
Just take it slowly. The best motivation is to make the computer do something
that you really want.
You have no reason to lack confidence since it's a completely new subject for
you.