1. The blog page is created by placing the category link in the menu. That way all the posts from one category are shown there. When you create a category you can choose what layout it should have – Right/Left sidebar or no sidebar at all. Then you place your posts in this category, and after you can go to menus (Appearance > Menus), and on the left side you should see ‘Categories’ dropdown. Inside should be your newly created category that you can place in your menu, so that when you click on them, you’ll be sent to the blog page with blog posts.
Only single post page has comments. Pages and posts are different things in wordpress, posts have comments, pages not (unless you customize it).
2. Your permalink will set your blog page automatically to the name of your category. If you put your page as posts (in Settings > Reading), in that case you should be able to just take that page you created and place it in your menu, and give the menu the name you wish. In Appearance > Menus, find that page you created for blogs, and place it in the menu. Then click on the menu on the right and change its name to ‘Blog’ – this will now show in the menu as ‘Blog’.