Ok, let's run through the setup for an Enhanced Portfolio.
Note, that I've already created a couple of Gallery Categories before moving through this process. If you're unfamiliar with Gallery Categories then take a quick look at this earlier Tutorial to understand that process.
1. Click Website
2. Click Pages
3. Click the + Portfolio Page button
4. Enter a Page Name
5. Enter a Page Heading
6. Set the Portfolio Contents to Manually select form Library
7. Set the Portfolio Style to either Gallery based or Gallery Category based
8. Hit Save
Once the Portfolio has saved, you can then scroll a little down the page to setup the Portfolio Contents
9. Click and Drag the categories of your choice from the available table on the right to the active Portfolio Contents table on the left.
(Make sure you grab from the top of the thumbnail where the grey "drag strip" appears)
Note that if you selected Gallery based Portfolio Style in step 7, then you'll see a list of available galleries here rather than categories.
10. Hit Save
If you now check your Live Site, you should find your new Portfolio lining up in your navigation strip!