Fibonacci expansion is usually used to forecast key levels and areas where a price movement will have a high probability of exhausting in relation to the previous correction.
Practical Exercise
1) Pick a currency pair, it can be any currency pair, any timeframe.
2) Based on the most recent development in price, apply the fibonacci expansion tool.
3) Post your exercise on the comment section in this thread.
4) Repeat this practice to gather a total of 10 examples.