Giday looks for a customer with that name in your ServiceM8 and uses it if it's there. If not, it creates one with their name and mobile.
A job is created against that customer as a Work Order, with what the caller said they need as the description, the address if one was given, and Giday marked as the source.
The caller's name, mobile and email (if they gave one) go on the job as the job contact.
The job is scheduled at the time that was booked, against the staff member you pick in your dashboard.
The caller gets their text confirmation and you get your text and email as usual. The ServiceM8 job is in addition to those, not instead of them.