Macbbok display not backlit

Hi,
I had my MacBook (1st Gen aluminum) sitting on a table one day and water spilled on the table and ran into the back bottom of the Macbook. Ever since then the display has not been lighting up but I can get the computer to work on an external display. This has been the computer's only problem. I'd like to do the fix myself.

1- what part needs replacing?
2- where do I find the replacement part?

Many thanks!

Apologies for misspelling MacBook.