Hi Rushabh,
I would love to assist but I have a small request. I stumbled upon erpnext and initially I was somewhat reluctant to look at it as it was a linux dev project. But after playing with it for some time I decided to at least have a look, and over come my lack of linux skill and upskill 
I have installed it a couple of times on a vm and I think im comfortable with at least getting it up and running.
My major issue is trying to contribute in a way I understand. I want to start to use the application more, get to learn more about its good and bad features and able to code features. But at this stage its slow as im trying to get the dev environment up and running in a way I can understand the code. I have submitted a post in the forum regarding this Pycharm Debugging but no response from anyone as yet. Im assuming that Pycharm or an ide is not used for dev. If I can get this working I can at least start to run around erpnext, learn more the flows and finally have a plan to contribute back the costing model I prefer. I did communicate to you the “exact” cost model, but I think the timing to doing this was to extensive and I was suggested to add this as a contribution.
All to happy to add what I learn, both towards the docs and features and bugs, but without an environment that will allow me to easily do this its going to be harder.
So if we can start with the dev docs - that would be great. As the objective is to get the community to contribute.
regards
Hemant