HTML provides a set of sectioning commands for dividing a document into a hierarchy: each section at the next lower level is numbered from 1. Thus, the number 2.4.1 refers to the first subsubsection of the fourth subsection of the first section.
The numbering of sections in Web 68 is handled automatically by both tang and weav. All you need to remember is that each section is either a level section or a plain section.