In one sentence, describe what the following article is about:

Take your strand of hair and lift it up a little. Remove the strip covering the adhesive on the bottom extension. Press on the bottom extension underneath the thin strand of hair you're lifting. Take the top extension. After removing the adhesive tape covering that extension, press on top of your strand of hair. The top and bottom extension should stick together. Then press them together with pliers for a few seconds to secure them. If the extensions are not sticking, you used too much hair in your strand. Gently brush some hair off the bottom extension. Move across your side part, repeating this process until you have added all the extensions. The precise number of extensions you are adding depends on the size of your head. You will likely use about 5 rows of hair extensions or more, depending on how voluminous you want your hairstyle to be.  If you plan to add extensions on the sides of your head, leave 1 inch (2.5 cm) of hair out horizontally, closest to the ear, and then continue applying the extensions. If you have a thin hairline, leave about 1 inch (2.5 cm) of hair out across your entire hairline before adding extensions, just to make sure that your hair has enough density to cover the tape-ins without making them noticeable.

Summary:
Attach the bottom extension under the thin portion of hair. Secure the top extension. Repeat the process.