如何在Xcode 4.2中将一个视图控制器调用到另一个视图控制器

i have two view controller firstviewconroller and secondviewcontroller. i have alert view in firstviewconroller now i want to goto second secondviewcontroller. clicking alert view button. guide me how to call secondviewcontroller using code.i'm new to this stuff. here is my alert view code.i have two view controller firstviewconroller a