Mani, I'd actually add that if you don't understand AEM in general, understanding forms will be a very hard learning path if you're coming from the Designer / Workbench environment.
Your best path to learning forms is to start with creating a "site". https://docs.adobe.com/docs/en/aem/6-1/develop/the-basics/website.html. This will give you a good understanding of how all of the "parts" fit together. "Templates", "Pages", "Designs", "Components". You need to understand those concepts before you'll make good progress with forms.
If you have the setup ready, you may want to start with managing forms  , which will help you get well versed with the UI that manages and give you the connection points for various functionalities available in AEM Forms. Secondly, you could start with authoring a form . The details can be found in the following docs:
Yes - we will add another Ask the Experts for Forms this year - join my blog for all Ask the Community Expert sessions - we post it there as well as a number of other community end points such as FaceBook and Linked in Groups.