How should I do this?

Simple, tu don't make it.
There's already a Geek club: link
Always check if the club already exists o not. If it doesn't, then tu simply make it and anunciarse it.

Well yes, I say tu should go right ahead & find a couple friends to help start tu off. Tell others about it por spreading the word around @ school & once numbers grow too much to fit in your house, try finding a public place to meet, but don't forget to keep saving up while there's only a few people/yes, tu do need money. Once you've hired out a hall o something, start advertising it online (because tu don't want strangers knowing your address!!) & if things continue to go well, then talk to some professionals about possibly making it into a real business (people pay for membership); seek help if that's what tu want to do. Good luck & have fun :)!!