The owner's manual will have a fuse box diagram showing the function of each fuse and its amperage. Generally, you'll find some fuses in the underhood fuse box and potentially others inside the vehicle, often near the driver's side kick panel or under the dash. There may also be relays involved that are not fuses but could be the cause of a problem.
Without your owner's manual, I cannot give you the exact locations. Searching online for "1999 Ford Windstar fuse box diagram" might yield a diagram you can use, but it's crucial to cross-reference that with your specific vehicle's labels. Incorrectly replacing fuses can cause further damage.
