By short: to create a good and secure web site - now this is a real professional job. It's almost like being a doctor. It's almost like being several doctors. If you are not a doctor, you must pay/hire one. Or learn almost everything a doctor knows. There is no place for amateurs.
To do what you intend to do, you must:
- learn how to use a graphical tool (Photoshop is the most famous, but the license is quite expensive)
- learn HTML
- learn CSS
- learn Data Base handling (MySQL is freeware)
- learn a server-side language (php is freeware)
You may also need to know the basics of XML and, probably AJAX.
Al these are minimum of you need to know.
See? There is room for 2-3 experienced people, and you want to do it by yourself in a minute, without learning anything. Of course, you may build yourself a small house without being an architect. But nobody will guarantee your house woun't collapse next storm. Even so, you must learn a little bit of Mechanics, Resistance Theory, Geology, Carpentry ... and stuffs like that. That will take you some time. But if you must do it by yourself, you must learn those things by yourself. Otherwise, you must hire a professional. There is no middle way.