If you get a blank php page showing in your wordpress site, then you can start adding code to it using webassist extensions. I don't have any tutorial on it.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.