Ok, I kinda overlooked that you're on a Live CD and not familiar with the commandline. That isn't a problem as Basileus already explained the way to do it from your desktop.
You asked what the various lines in my syntax example mean. But, as you're new to this, I'm a bit worried that it might be to much in one go.
The first line tells the kernel that to execute the script properly it needs to use a specific interface with it's syntax. In this case, the interface is named "BASH". There are a few others, but bash is the most widespread in Linux.
The second and third line are basicaly equal. This is an abstract way to tell the reader that (s)he needs to replace that line with the command that needs to be executed, followed by the command's options.
The fourth line is the (my) way to tell the reader to continue with the previous lines as necesary.
The last line tells the kernel that it reached the end of the script and that if it could be executed normaly it should exit with an error status of 0 (as in zero) That is standard behaviour and IMHO a good programmer should always end a script nicely (for the kernel, not me
Next, you where a bit confused about
S<2 digit bootcode>scriptname
Again, the way I wrote it tells the understanding reader to replace the part between the < and > with a 2 digit number and the name of the script. It's not used inside
the script, it's intended to give the script a name and a place in the sequence of execution by the kernel when booting. Actually, it's a link to the actual script in your home directory.
As I've said, I'm afraid that this might be a bit to much to comprehend in one go for a newbee. So if you don't understand it's not a problem. I too needed time to understand this. Use it as a brief introduction to writing scripts and read it again when you've got to grips with Linux and it's versatility.