Make my PHP script to add a row into my Google Big Query table

I've got a projet set up with Google Big Query and billing enabled and an API key created on my google account. I've created a first dataset and a table with a very simple schema (just 2 fields). I have this php script (see attachment) to write a row each time it is called. I'm running it in a subfolder on my hosting server (not on google cloud) with php and https enabled. I know I'm missing the auth configuration (maybe something else) but I just cant get how to do it. I need you to get the script to work to write data into the table and then show me how to do it next time. The script is just 50 lines by the way. I can give the needed access to the project's googe account and the ftp access to the host. I don't have access to the host config, you can its php info here: [login to view URL] Please start your bid with the phrase "google cloud" or else I will ignore it, and tell me whether what i'm asking is possible or if I need to host the app on google app engine or something else.