Don’t worry, English isn’t my native language either
The webhooks are discussed in the docs over here, and contain some example code to send information to Librato. You’ll have to change the webhook code to match the Google Sheets API, which can be found over here. This might also contain some useful information regarding the headers that are necessary.
So, basically, you can continuously poll those pins to see if they’re high, and then send a SSE, which in turn sends a webhook to the page you’ve specified. You can also attach interrupts to those pins and have them send that SSE, which is a bit nicer. The challenge lies in getting the webhook right, the code on the Photon is very simple.
Mind you that the Photon code for this would be almost identical to the one that would be used if you were to use IFTTT. Just trying to provide an easy as possible alternative, if you don’t like it, then don’t use it