How to include my blog on just one page in the menu

Hi everyone,

In my menu I have six pages including one that I’d like to be my blog:

Home | About | Blog | This | That | etc.

So the Front Page is Home and I’d like Blog to show my posts. But I can’t seem to do this. Can anyone help please?

Note:
The theme I started with doesn’t support custom menus so I’ve created six pages, page three being Blog.

They’ve each got separate templates but I can’t find what to put on the blog template to get it to show posts.

I’ve been to Settings>Reading and tried setting ‘Front pages displays’ like this:
Front Page: Home,
Posts Page: Blog

…but that just results in both pages showing the Home page.

If anyone can help that would be great!

Cheers,
Learni