Your source is woefully inadequate if you want to understand how cladistics is done. It is done with DNA comparisons. A “clade” is a branch that all share the same evolutionary feature (even if they lose it), but cladograms are constructed by DNA analysis.
But of course you wouldn't be expected to know that if you rely on Creationist sources, they misrepresent the science they attempt to debunk out of necessity.
Clos is a Creationist?