In order to do so, you need to

1- access your ftp and add the following into your /conf/vhost.conf file:

<Directory /home/httpd/vhosts/DOMAIN_NAME_WITHOUT_PREFIX_HERE/httpdocs/FULL_PATH_TO_PROTECT>
    AllowOverride AuthConfig
</Directory>

2- in the directory to protect, create a file named .htaccess (dot htaccess) that will contain the following:

AuthUserFile /home/httpd/vhosts/DOMAIN_NAME_WITHOUT_PREFIX_HERE/tmp/.htpasswd
AuthName "Restricted Area"
AuthType Basic
AuthGroupFile /dev/null
require valid-user

3- in the folder /tmp, create a file called .htpasswd (dot htpasswd) and include your user/password combination like so:

test:jQ7u9TBnY2LNI

Please note that the password is encrypted. To get your own encrypted password, look here.

We have setup a test page for you to try.
Use the following credentials:

user: testuser
password: testpassword

and click this link to test

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