If you want to start SharePoint 2010 workflow by using Rich Forms you need to do the following steps:
- At first you will need to configure Sharepoint 2013 workflow, which will start your Sharepoint 2010 workflow.
You can find "How to trigger a SharePoint 2010 workflow from a SharePoint 2013 workflow" here:
- Then you can use skybow Rich Forms "Start Workflow" action on your button which will trigger your configured SharePoint 2013 workflow.
And it's all !!
Hope it helps.