Thanks for writing in! When you install Ethos 1 demo, only the settings is imported because the homepage of Ethos 1 is displaying the latest posts or the blog index as the homepage. If you do not have any posts yet, then nothing will display in your homepage.
If you have several post already and nothing is displayed in the homepage, that is because in the Ethos 1 demo, Filtered index is enabled. Enabling the filterable index will bypass the standard output of your blog page, allowing you to specify categories to highlight. Upon selecting this option, a text input will appear to enter in the IDs of the categories you would like to showcase. This input accepts a list of numeric IDs separated by a comma (e.g. 14, 1, 817). You can disable this option by going to X > Theme Options > Ethos > Filterable index.
Let us know how it goes.