These levels highlight where the price has reacted, in such a way, as to reverse (often referenced as "bouncing") or consolidate.
Levels can include a combination of candle bodies and wicks and, therefore, can be subjective.
To verify levels, the price should have reached/hit levels on multiple occasions, and levels on higher time frames (ie 4hr and above) often play a more significant role in price action than levels on lower time frames.
Once Support is broken, it will/may become Resistance, and therefore, once Resistance is broken, the level will/may become Support.
These levels are often easier to verify when viewing a Line Chart.