Click on Amiri's Portrait.
Above the quickslots you'll see a stylised "A" and "B"
Click on "A" (for Abilities) to open another row with Icons like Rage, Fight defensive, Power Attack and so on.
Click on "B" (for Belt) to open the quick access to the belt items (potions, wands, scrolls...)
Also, in the case of spell casters, there is a third stylized letter, an "S". (Left "S", Middle "A", Right "B"). The "S" is for spells.
As for Power Attack (and some others), there is a thin vertical stripe to the right of each portrait, and there are very tiny icons in that stripe. Hold the mouse over each one for a moment or two and it will tell you what it is. If memory serves me correctly, Power Attack is a blue circle.
-- david
It should also be noted that you can drag icons from the Spells, Abilities, and Belt menus to the shortcuts right below them for easy access at all times.
One quality of life improvement would be the ability to turn off things being automatically added to these shortcuts. It's kind of annoying to have these changed every time you memorize different spells. It works this way for the shortcuts on the left side, why not here too?