There is currently no clan system here for SF on Aeria , but they are meant to be bringing one back from the old system we had back in www.ijji.com
, however there is no ETA as to when it will occur , many people think it will be in this coming update which is around the last week of the month , if not the next.
I myself hope it is this one.
To make a clan you need to think of a name/word that nobody else has used , which is difficult to determine with no clan ranking list yet , so for the time being what i would do , is look for someone who is recruiting people to a clan , join them , or start one yourself by making one with a name you thought of.
An original word is likely to be taken already so think carefully before you make one.
Best Of Luck!