A shorter chart interval used to refine entries and see the order of events inside a larger bar.
How timeframes stack up. A daily candle is not different data, only coarser data: it opens where the first six-hour candle opened, closes where the last one closed, and its wicks reach the highest and lowest prices any of the four touched.
Dropping from a 1-hour chart to a 5-minute chart lets you see whether the hour's high came before or after its low, where volume clustered, and whether a rejection was one fast spike or persistent selling.
Traders use lower timeframes to tighten risk: instead of risking the full range of an hourly bar, wait for a small structure to form at your level and place the stop beyond that. Same idea, smaller risk per trade, which raises the r-multiple of the same target.
The danger is that noise grows as the interval shrinks. On a 15-second chart every wiggle looks like a reversal, commissions and bid-ask-spread become a larger share of the move, and overtrading becomes very easy. Use the lower timeframe for execution only, not for changing your mind about direction.