I need help on how to build a guild cape

I just need to know the requirments for building a cape? Can anyone help me...

Sure ;-)

just go to the guild registrar in Ascalon City (if you are in pre-searing) and pay him the gold required to form a guild. After that, he requires 2 plat (2000 gold which will appear as 2 iron-looking bars next to your gold in your inventory). After paying this fee, a screen appears to create a cape. There are many many designs to mess with, and then anyone who joins your guild thereafter will have the cape you designed, to show off and let others know their affiliation.

You can change the cape later, I think at least, with 2000 more gold. I haven't tried however

I took the liberty of posting a screenshot for you. Note the bar next to the gold icon in the bottom right.

The images you see are some of the designs to choose from. There are many more to see and mess with