Guides to create an online mobile store app

Question

Good day sir/ma

Please I need someone to guide me on how to build a completely working mobile store app that can be used offline and online. I just learnt ASP .Net so am new to web programming but I uses c# freelancely for desktop applications.

 

This mobile store app should allow user to view and buy products with/without registration. please I will like hints on list of third party libraries(e.g for online payment and verification) needed, how to structure and some functions/methods I will need.

 

Thanks in advance for your usuall cooperation.