How to place banner?

how is the question related to WordPress?

if it is for a WordPress site, you possibly could edit header.php of your theme and add a new div for the banner just within the outermost div of the html structure; then position the div using css; https://www.w3schools.com/css/css_positioning.asp

please post a link to your site to get more suggestions.

Here : https://mindblowingtorrents.co.cc

where exactly do you want to place the banner?

in the sidebar but orientated right?
or on the right outside the existing boundaries of the theme?

what kind of banner?
a linked image? or adsense?