[Plugin: Blog-in-Blog] Beginner Question. How to put category of posts in page

First you need to find the ‘slug’ of the category you want on a Page. Go to Admin->Posts->Categories and copy the slug (in the Slug column) for the category.

Then, edit the Page (not Post) where you want the Posts in the Category to appear. Enter the shortcode below, replacing my-category-slug with the slug you copied:

[blog_in_blog category_slug='my-category-slug' ]

Update (or Publish) the Page.

Now when you view the Page, you should see Posts in your category.

Would it be possible to add more than one category per blog?

Like:

[blog_in_blog category_slug=’my-category-slug,category-2′ ]

any idea about the syntax?

That does not seem to be supported in the current version.