> The way you are trying should'n work as you are creating a page by
> creating a menu item. Rather you should visit you block administration
> page at www.yoursite.comadmin/structure/block . Here you will see list
> of all your blocks and available regions in your theme to assign to
> the blocks.
 

> Here is a screen shot![enter image description here][1]. In the screen
> shot where you are seeing the select list with none as selected this
> list will let you place your block in the available region.


  

[1]: https://i.sstatic.net/hFP5U.png