Creating webviews can be a daunting task. Your best bet to get started is by downloading the vCenter Orchestrator Developer's guide and going to page 298. Then, follow the step-by-step instructions on how to Create a Simple Web View Using the Default Template. The guide provides a wealth of information around the technology used in vCO webviews as well as sample usage and syntax.
In addition to the resource mentioned above, we recently published part 3 in our series on a self service provisioning portal that includes step by step details on creating a webview. Create a Simple vCO Self Service VM Provisioning Portal - Part 3