look at PP, C = Pivot point
or
calculate
PP = (H + L + 2C) / 3
to see fibo 50%, drag it on chartsimply
or
Fibo 50% = (H + L) / 2
Please make some research, that tricks are coming from along time of huge experience and trading, studing in universities, schools, as well as reading ebooks, and sharing with experts traders in the world.
nothing come easy
Good luck