Fib-retracement is used to identify the levels or zones where price could reverse or consolidate. It can also be treated as Support/Resistance.
The levels of Fib-retracement
0.236 - used to identify shallow retracement
0.382 - common retracement level
0.5 - not a Fibonacci ratio but still used by technical analyst
0.618 - golden ratio, is significant for technical analysis
0.786, 1, 1.618 so on...
Are all other levels of Fib-retracement.
To use this setup find the support/resistance levels and draw till its previous resistance/support level.