The location of this file: (and the data for the .htaccess file):
AuthUserFile /usr/local/apache2/htdocs/_Sandbox/access_control/.htpasswd AuthName PasswordArea AuthType Basic require valid-user
Upload this form, an _htaccess and an _htpasswd file in the folder you wish to protect. Make sure both of them are chmod(777).
Run this form, change their names to .htaccess and .htpasswd, and voila!