OL candle indicates that candle's Open and Low prices are same and a Long trade can be taken with a stoploss below candle low.
OH candle indicates that candle's Open and High prices are same and a SHORT trade can be taken with a stoploss above candle high.
Candles with navy blue colour indicates an Inside Bar. An is a common pattern where the high and low of one candle occur inside the high and low of the prior candle. shows a contraction in and are often a continuation pattern. Previous candle (prior candle to ) is known as "Mother candle" and trades can be taken on breakout from "Mother candle" , in the direction of breakout and keeping a stoploss below/above "Mother candle".
This script can be used in any time frame. Smaller time frames generate more signals compared to higher time frames.