How do I use cookies to let visitors access to the downloads page of my website

I want visitors开发者_运维问答 to my website to fill out a contact form before they can access the downloads page. I am looking for online resources or examples. The only ones I can find are username and password authentication which I don't need. I am hoping to do it in PHP. At the moment my Contact form emails me their details but anyone can access the downloads page.

Thank you

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You're not giving us much to go on!

Based on your tags I assume your developing in php. This tutorial should give you what you need Website Authentication - a simple PHP sample