How to scalp other session?

I saw the thread abt the Asian session scalping .

sometimes after the US session closes awaiting asian session the next day , there is a great sell off or rally ( sometimes ) .

for US , the time to scalp is 10 PM GMT .

for Euro and cable , the time to scalp is earlier like 8 PM GMT .

any idea how to scalp .

set triggers within a range like 20 pips in 2 directions ?