Hi GonzaloGM, your question is more related to designing a proper theme. It would be best for you to ask the question in the general forum regarding theme development. If you search here in wordpress.org you will find lots of articles related to the proper way of coding themes. Also what you can do is check the default theme against your theme and see what is the difference.
Once you have your theme up and running again please come back here if you have any issues with the plugin.
If you can mark this support thread as resolved that would be much appreciated since your question is not related to the plugin but more to the development of the theme.
Kind regards