Template guidelines?

I'm working with Zoho Invoice for more than two years and it is still very cumbersome to build on templates.
It seems that some IDs, tables and attributes are mandatory. On the other side, it seems to be impossible to build a tabeless design. And what about page breaks? It seems that a special nesting of tables is needed to make a consistent page break possible...
Why doesn't Zoho publish some kind of Templating Guide?