Hair extensions are often called hair weaves. They come in many styles, and there are many methods of affixing them. A common and easier style is the hair-weave track, in which the hair is sewn together in a straight length. The seam at the top of the piece is used to affix the extension. Hair-weave tracks can be applied by actually sewing them to your real hair or by gluing them in. By far, the easiest way to put in a hair-weave track is via the glue method.
Cut the tracks to the desired width. Generally, they should cover the area between your left and right hairline in the back, and from the center part to the hairline on the sides.
Starting in the back, make a part about 1 inch from the nape from left to right. Lift the upper hair away from this section and clip it.
Smooth down the remaining hair on the nape of the neck. This leaves you with a clean part in which to apply the tracks.
Apply a thin bead of bonding glue along the seam of the track. Do not apply it directly to the head, as it can run and mix with your hair.
Place the track into the part on your head and press firmly. Hold the track in place for about 30 seconds, then use the blow dryer to set the bonding glue. Blow-dry for 1 minute, moving the heated air along the top of the track.
Repeat this process until all of the tracks are in place, smoothing the natural hair down over the tracks as you go.
Test the bonding glue on your skin 24 hours prior to application, to make sure it doesn't irritate your skin or cause any allergic reactions.