I am a wordpress newbie and wonder whether this is possible; I used wordpress to create a website with different pages and subpages. Now I would like that new posts appear only under certain page, how can I do this? I tried but new posts always go under main page
You can assign any page-- "Page", not blog post or CPT post/page-- to be the "blog posts" page by going to
wp-admin->Settings->Reading, clicking the "A static page" radio box and selecting a static home page and blog page from the drop down menus.
If that isn't what you want, or if that doesn't work, then you will need to explain things a lot better.