If you don't already know how to code, you're a ways away from getting this to work. If you want a web page you'll have to learn how to configure it, code in HTML, php, pearl or some other web language. And make the page available publicly, with either a static address or more likely dynamic DNS. Then on the PC, you will need to select a language to code the relay program, such as VB, C or C++. Same for the microprocessor; select ASM, C or whatever language is supported. Depending on your system architecture, computer A may only need a browser. And depending on what you use to program your web page, your relay function may be embedded in the web page.