Sidebar: Different for each page

I don’t understand the question? You want to display different content in the sidebar for different pages?

created a Category called Sidebar… but it automatically places any post under this category on all pages with sidebars.

That’s what confuses me.^^^

One way is to create Page Templates and new sidebar PHP files and use file includes to call those sidebars. For instance, lets say you have a page called “Contact” and want to include specific info in the sidebar on that page.

Create a new Page Template called “contact” (you can use your theme’s page.php file to guide you) and insert the following at the top…

<?php
/*
Template Name: Contact
*/
?>

Then when you create the contact page you can select the contact page template from the drop down menu.

Next, create a new sidebar.php file – call it whatever you want but for sake of simplicity lets call it contact-sidebar.php. Again, use your theme’s sidebar.php file to guide you.

In your newly created Contact Page Template use a file include like this…

<?php include (TEMPLATEPATH . '/contact-sidebar.php'); ?>

More reading:
https://codex.www.ads-software.com/Pages
https://codex.www.ads-software.com/Pages#Page_Templates

works good for me – to bad you can’t use different widgets for each page/sidebar – – or can u? (doubts it)

you can write different text in postmeta and call it in sidebar.