Post Timeline has 23 Templates in total, including Vertical, Horizontal, and One-Side Timeline Templates. Once you have created your timeline posts, you can hook any template to it and all your posts will render using that selected template. To select a template, all you need to do is to write the attribute in your shortcode named as a template with its value.
The Timeline Template page can help you to get the right code of the template and its shortcode, you can click on the selected template and it will show a dummy timeline with the template code as shown in the image below.
The shortcode can be copied from the blue highlighted line, add the category ID into it and paste it into your WordPress page to show that category timeline.