Sale and purchase platform - duplicate theme - creating a main index.php

[GermanPrestaNewbie]

Hello everyone, I'm new here and I'm not that experienced - but I'll try to give my best!

 

 

What:
I want to create a webshop where the customer can BUY from me and SALE their stuff to me. On the index.php (home page) the customer should have the choice where he want to go - to the purchase section or to the sale section.

 

 

 

My problem:

I want to use the default-theme. Now i have to create a "top" home page, where the customer can choose between the two sections. How should i do this for the best and easiest result? 

 

 

 

My Idea:

Maybe double the theme and adjust one of them for the sale section?

If I would do this there would be an index.php for the sale section and an index.php for the purchase section. Now i would need a new "top" index.php (see the reference). Can i do all this in the backend or should i do this in an IDE and just with copy paste in the folders?

Or do i have to do this with the controllers? Any advices and ideas?

 

 

 

Reference:

It should be like www.rebuy.de - I'll hope to post the link is ok?

 

 

 

Sorry for my english, I hope you'll understand what I mean. Thanks a lot!

 

 

P.S.:  It's for my bachelor's degree so please just post helpful links, advices and ideas and not finished code-snippets, thank you!

Edited July 1, 2015 by GermanPrestaNewbie (see edit history)