Default [Q] xperia u GB to KK [noob]

I wish to upgrade my stock GB ROM to Kitkat ..i have a xperia u st25i

i have unlocked the bootloader

flashed a kernel with root priveleges but has no clockwork mod integrated with it ...

now i am having a hard time in proceeding ahead , should i just flash a custom rom ? or go and flash a CWM ? what am i suppose to do