Script report writing for pixel perfect reports

I have read https://frappe.io/docs/user/en/guides/reports-and-printing/how-to-make-script-reports

I still don’t understand it as I come from crystal reports background where we put in fields and multiple tables within same report at pixel positions so that we can print on top of pre-printed stationary.

I can’t find any other tutorial / example to take me through this. Any help will be appreciated.