How to backtest price action?

let me explain How i trade intraday?

one day before i specially look for double top, double bottom or head & shoulder…
then i see what is the trend… uptrend or downtrend or sideways

if uptrend, i look for continuation trade after retest or trend reversal with M pattern for short
if downtrend, i look for continuation trade after retest or trend reversal with W pattern for long
if sideways, i look for channel breakout or breakdown with restest

and i get 50% win rate on this trading style

now please help me how to backtest?