how to add html or php code into vbulletin?

[国际贸易]

http://www.vbulletin.com/docs/html/template_conditionals
http://www.vbulletin.com/forum/showthread.php?t=141232
http://www.vbulletin.com/forum/showthread.php?p=1066718#post1066718
http://www.vbulletin.com/docs/html/templates_externalfiles