Need php help for Google Indexing API for Google Jobs

I have a job website, I want to update my new jobs to Google by using Google Indexing API.

I have done all steps like creating a service account, have given access in Google webmaster for my API email.

Now I came to the last step where I have to create PHP code.

https://developers.google.com/search/apis/indexing-api/v3/using-api

Here they give the following example:

POST https://indexing.googleapis.com/v3/urlNotifications:publish
{
  "url": "https://careers.google.com/jobs/google/technical-writer",
  "type": "URL_UPDATED"
}

But I do not know where to code this, what PHP code I need to create to update Google for new jobs.

I have never used Google API before in my life.

Can anyone help me to update Google for new jobs using Google Indexing API?