Thanks to Mike, I’m able to create sub domain by myself. I think doing with sub domain is more appropriate than using folders since they do not really belong to my main site; moreover, my main site’s folder will be neater.
I hope I will have time to revamp Smoke Slayer and then I will probably get a new domain name for it before I try to exchange links with big websites. The intention behind the site is to discourage smoking and I believe I should not waste my effort and stop it halfway.