ServiceM8 free account - create API to post a new job from a Google Sheet?

I have a free ServiceM8 account. I got some wrong info from support about Zapier (turns out it cannot be used on a free account).

Could someone confirm that a Free account can set up an API? It is registered as a developer account.

Could someone confirm that the following can be done with an API?

When a new record is added to a google sheet, post the details as a new job to ServiceM8.

The developer documentation seems fairly sparse. I cannot even find a list of field names that can be updated.

is RestAPI a suitable solution?

This does not help me a lot.

Any links to helpful information would be appreciated.

I have limited experience in developing API but with suitable information and the help of API I can usually get things done.