Hello @Aravind ,
Thank you for the outreach, and welcome to the HiveMQ Community!
Based on the information provided, it seems that first and foremost we may need to look into the MQTT client that will be used. Reviewing the EWON boards, it does appear that they have an MQTT client available, and some details on implementation available on their forums here. This may be a great place to start, as it offers introductory implementation details.
As for TLS configuration, the server CA file for HiveMQ Cloud implementations is available via our FAQ page, or linked here.
As it sounds like this project will rely on the MQTT protocol, and will require some custom implementation, I would also recommend reviewing our MQTT essentials series, if you have not already reviewed it in your research, as this offers some great insight into MQTT as a whole - this can be viewed here.
Best,
Aaron from the HiveMQ Team