I've prepared my simple html website on my small local pc. Now I wish to put just the primary websites without administrator after sales pages on server. I attempted several queries on the internet but useless.

Joomla pages aren't 'simple html pages,' they're complex .php scripts. You cannot leave the administrator after sales pages from the server since they're needed by Joomla to operate. You skill, however, is modify your server configuration (I personally use Apache2) to create the administrator directory inaccessible to browsers. I actually do this routinely on my small Joomla sites inside a virtualhost block.

# Deny access to Joomla administrator directory
<Directory "/your/joomla/install/administrator/">
Order Allow,Deny
</Directory>

You will need to comment this out and restart Apache to gain access to the administrator console.