This video shows you the basics for using a Presta Valve.
• First identify if you have a Presta Valve
• Next removed the plastic valve cap
• Unscrew the valve lock-nut until it stops
• Tap the end of the valve to release the back pressure
• Attach your pump head (use valve adapter if needed) and pump up your tire
• Remove your pump head
• Lightly tighten down the lock-nut to hold the valve pin closed
• Replace your plastic valve cap