Begin your work on the kitchen garden windows from outside. Cut through any sealant such as caulking. The casing around the window should be scored to release paint and not harm the drywall. Pry off the interior casing by using a pry bar. Then the window should be pulled out. If you would like to learn more about this, please view publisher site.
This takes two people, one person on the inside slowly pushes the window out while the person on the outside catches it and lifts it down, if the outside person needs to go down a ladder then the person on the inside should come out and help.
Find the center mark on the window frame to center your new window. Install an aluminum drip cap. Add spacer blocks so the window can be elevated to the correct level line. Lift the window up to the opening and put in place.
Use shims to level it and then screw into the rough opening. To add support on the outside of the window, screw in brackets. Measure the trim on the house, cut at a 45 degree angle. Screw into side of house. Caulk around the window.
Put in insulation inside the house i.e. in the space that is between the frame of the window and the opening. This keeps drafts out. At this point the inside casing can be attached. Measure it, cut and then nail it in. Caulk seams, fill in holes and you are done.
You can get a kit that is customized for your kitchen garden windows. You can get this from a local retailer or an expert who can come to your home for an inspection before making a recommendation. The frames come in vinyl, aluminum or wood.