[Question] How should I build an architecture for such a website?

I recently want to build such a website, of course Asp.net, but I have no experience, so I 'd like to ask you

The website information can be imported to the local device.
Import method:
(1) directly download and save as an Excel file
(2) Use RSS
(3) create an application locallyProgram, Regularly update local data, consistent with the website

The first method is well implemented.
However, the two following methods do not really know how to implement them.

The most important thing to do is to implement such a function. Therefore, we do not know how to design this website.

I am not very grateful to have some suggestions from experienced users. Thank you!