You are talking about the vents on the very end sides of the dashboard? For those,you just use a flat tipped tool like a slotted screwdriver and (carefully) insert it into the very side of the vent.The vents just snap into place,and should pop out of place if you slightly move the tool to the side.Not too much or your liable to crack the plastic.Do both sides of the vent like this.To install,just push it back in until it clicks or you feel it catch.
How are they broken? Is it that when you turn the wheel to adjust the left/right angle,some of the slats dont move easily...and it appears the slide control is pushed in more?If so,it's a fairly common problem on Fords.It's not actually broken.It's just the very upper and lower section of the vent expands somewhat over time and the directional slats pop out of their slots.