Note: This article applies for the themes that use the Custom menus functionality within the Appearance » Menus section to build the main navigation.
If you have different categories of posts and you would like to separate them into different blog pages, the easiest way to do this would be to insert a link to the category archive into the menu. For example, if you have the categories “Lifestyle” and “Business” and you would like to have a blog page containing your “Business” posts only, you have to go to Appearance » Menus, from the “Categories” section select the “Business” category and click on the “Add to menu” button:
After that just save the changes to your menu and your new “Business” menu item will link to a blog page containing the “Business” posts only.
Please note that the “Categories” section may not be displayed by default on the Menus page and in order to display it, you have to click on the “Screen Options” button located to the top right section of the Menus page and from the options that will get displayed, you have to make sure that the “Categories” option is checked.