in a bowl take soya sauce , fish sauce , oyster sauce , white vinegar , mix everything . grate ginger and add the sauce, cut the capsicum in moon shape thinly. add little cooking oil in wok and fry beef about 10 minutes. add sauce made with ginger . mix and add Chinese salt and salt. mix and add Capsicum. the heat is very high and do not cook the Capsicum too much. this Capsicum will be ready 2-3 minute