Found by using the "search" function at the top of the page:
http://manual.b2evolution.net/Remove_the_sidebar

jj.

yap! I've read and tried that a few times but it didnt work. I tried changing my skin frm city_in_evo to custom and it worked.

right now, Im back with city_in_evo coz it is what I really like and Im still trying to solve my prblem.

do you have any idea?

To remove the categories section, either delete or comment out this section:

<?php 
/* ------------------------ CALL THE CATEGORIES PLUGIN -------------------------
 * customize your categories by adding parameters to the plugin's array. see 
 * http://doc.b2evolution.net/v-1-9/plugins/categories_plugin.html#methodSkinTag 
 * or plugins/_categories.plugin.php for details
 */
$Plugins->call_by_code( 'evo_Cats', array( // Add parameters below:
	) );
// --------------------------- END OF CATEGORIES ---------------------------- ?>

jj.

Ok. I'll try again later.

Next, how to add items on the sidebar and below the header. I wanna add links, banners and adsense but I've been trying and its not working.

Like I said, when I changed my skin, it worked. I was able to add and delete anything I wanted.

But when using city_in_evo skin, nothing happens.

Are you editing the files in that skin's folder? (Don't laugh - it's a common mistake to edit the files in the wrong skin!)

Its fixed already! I edited the main.php under www/skins/city_in_evo

Thanks for your help guys!