How do I fix MacBook Air to turn on after spilling water on laptop

The fix is to contact Apple Directly (https://support.apple.com/en-us/HT201232) and set up a Genius Bar appointment at the nearest Apple Store or at the nearest Apple Authorized Service Provider and have the Mac evaluated.

If the spill was so bad as to cause the Mac to stop working, you need to get it to Apple for a hands-on evaluation.

PS: seems your Support article link, picked up a defect ~ one character extra!

• Contact Apple for support and service - Apple Support

//support.apple.com/en-us/HT201232

This is the same link, with the last character removed: " ) "

OOPs. Missed a space after the URL before the parenthesis.