Accepted answer
Short answer: Rules explain how the round works; hierarchy explains which hand beats another.
How I check this as a player
I use rules for actions and hierarchy for comparison.
What it changes at the table
Both are needed before reading app or APK claims.
Safety note
This site is an independent 3Patti guide. I use these answers for learning rules, comparing app claims and spotting risky wording; we do not operate real-money games, process payments, or guarantee APK safety, winnings, withdrawals or bonuses.