The first step to creating a contact form for your web site is to create the form. I use Dreamweaver to create the form and it is a pretty straight-forward "click and build" process. Getting the form to work takes an additional step because the form will need to "cooperate" with another file, which is strictly code, and that is the php script.
Finding some php script that drives a contact form on the web is easy. Just Google something like "php contact form". It's only a dozen lines of code or so. Find one you like, copy it, save it as a .php page, and upload it to your server and then be sure the form posts the action to it. You have to be sure that the naming of things like email, message, etc. is the same, but if you can read, that's not terribly difficult. Putting in your email address, your URL, etc. is kind of like the old game "Operation" - just don't touch anything next to it. One erased semicolon and the patient is dead!
After that it gets tricky.