Hi Sukhdeep, unfortunately there is no straight forward way to do what you are trying to achieve, and I suspect that you are also looking to take your months of data with it. Your options are as follows:
You utilise the platform’s Module functionality and attempt to wrap the required parts of App A into a module and deploy it into App B. This is new functionality and is an approach that you could explore.
Using App A as your “Guide”, rebuild the functionality into App B. I think you need to evaluate how long you think it would take to rebuild App A in App B. If it is less than a few days it’s probably your better and safe option. If it looks like a mountain to climb, then go the Modules route, but that route is also not without its challenges.
Either way you will have to write imports and exports in Apps A&B respectively, in order to bring your historic data across reliably.
This advice is BROAD, based on the very little I know about your two Apps and what you are trying to achieve. I hope it helps. Please get back if you need further advice.
Regards - Mark P