Help Please Don't Know Where to Start with a string.

Hey there, I am super new to JavaScript and don't even know where to start with this problem.

I am looking to make a conversion script that will convert lengths, volumes and weights. But the user inputs the question as follows; " How many (variable) are there in (#) (variable)?"

The script must be able to make the conversion but also validate it so that you don't end up trying to convert a length into a volume.

Can someone please direct me to what I should be doing? I am hopelessly stuck right at the moment.

Please look at my signature.
Download JLA which is especially designed for js newbies.
You will find what you want.
Good luck!:)

Hey there, I am super new to JavaScript and don't even know where to start with this problem.
Can you show us some of your tries, at least?

That's the thing, I don't know where to start so I don't have any tries yet. I am still new enough to JavaScript to not know enough to even give it a try. Just looking for some direction at where to start and give it a shot.