That’s not Sage specific. You’re currently on the homepage’s query which will give you its title, thumbnail, …etc. That’s of course unless you you’ve set your homepage to display latest posts.
If you need to grab blog posts or other custom post type, you’ll need to create a custom query for them as you can see here.
What’s related to sage and will make your life easier is Sage Directives.
Thank you, i was thinking wp_query is for custom query not for simple post. But now i know. Thank’s you. Here is the code actually if you got the same problem :