I am not sure, if I understand the question properly, but if you want to display the subitems of "publicaciones" on the page "home" by using the CMSDataList component (I assume you are using the web part, not user control in aspx templates), then you simply specify the Path property in the web part properties. I don't know how the page alias path for "publicaciones" looks like, but I assume it would be something like "/publicaciones", so you add only "/%" to show children items, which means the path will be something like "/publicaciones/%". You can also use the path selector on the given property. If this doesn't answer your question, please provide more details (screenshots of your setup and such).
Boris