I am very new to K2.
I am using Purity III as template and Joomla 3.6. with K2

I want to put content into several different categories. (eg. SPORT, POLITICS, LIFESTYLE..)
On the frontpage I would like to show the top 3 new items of every category - as teaser (Headline, Introtext, Image)
So I need to show K2-Categories on the Home-Menu... But I only managed to select ONE Category.. I want all categories to show up

like:
__________________________
POLITICS
Teaser 1

---

Teaser 2

---

Teaser 3
__________________________
SPORT
Teaser 1

---

Teaser 2

---

Teaser 3
__________________________

How can I accomplish this..?
Is there a (paid) component to achieve this ?

There are two ways to achieve this.

a) Use the latest items from category menu item where you can manually select categories and pull x items.

b) Use a K2 categories menu item where you can only display the subcategories block.