create .htaccess and .htpasswd in this folder
.htaccess
AuthType Basic AuthName "restricted area" AuthUserFile /thefolder/.htpasswd require valid-user
.htpasswd file
user:csmBH6tTLNZBE
generate the pair user:password here: http://css-tricks.com/easily-password-protect-a-website-or-subdirectory/
check out the css-tricks for more details