Set the first setting, ExtraQuickSlots, to the Extra Quickslots you want. For example, entering 3 will add 3 quickslots to the existing 8 in the base game for a total of 11.
Restart the game. (Exit and "Start modded" in r2modman again)
Restarting is required whenever this value is changed. Extra Quick Slots can currently only be added when the game first starts.
Configuring Hotkeys
The Extra Quick Slots will be at the top of the Quick Slots section of the Keyboard settings.
Configure them to whatever you like, keeping in mind keys may already be assigned elsewhere.
Assign Items or Skills to your new slots.
Alignment Options
CenterQuickslotPanel - Just like it sounds, centers the QuickSlot bar to the horizontal center of the screen. You will probably need to make additional adjustments as the QuickSlot and Stability Bars will likely overlap.
QuickSlotBarAlignmentOptions
MoveQuickSlotAboveStability: Moves the QuickSlot Bar above the Stability Bar.
MoveStabilityAboveQuickSlot: Moves the Stability Bar above the QuickSlot Bar.