Help with LED lights (not sure if this is the right place)

As the topic states I'm not too sure on where to find some help for this but I thought I would try here. I am helping with a project in which I need to make a string of alternating red and orange LED that is powered by a 12v power supply. I can solder OK but I dont know how I am going to make this, I need something thing to put the LED's on in a line formation and i need something that will amke them flash alteratly I.E. XOXOXOXO
OXOXOXOX

Could any of you point me in the right direction?

THANK YOU!!

P.S. sorry for the re-post but i was informed to post here