Hello quebecguitare,
I was looking for a solution to do the same & the following helped me achieve it. See if this works for you.
1. Create a Menu title (eg: Works/anything that you want) and Menu Item Type should be "Latest items from (one or more) users or categories" in K2.
2. Go to the "Options" tab in the Menu title creation window & set the content source to either Categories or Users (based on the way you're data is stored) from the "Content Source" section. Set the number of cols & max number of items as per your requirements.
3. If you selected 'categories' as the content source, then scroll down in the same options tab and you'll find a "Category Settings" option. Select the categories you want using the button there (click to select one or more categories).
4. Modify the other settings in the "Options" tab as per your requirements!
Hope this helps
Regards!