HTML editing

The the best way to make changes to a self-hosted WordPress theme is via a child theme, so your tweaks won’t be overwritten every time you update the theme. Here are some guides in case you haven’t made one before:

http://codex.wordpress.org/Child_Themes
https://www.smashingmagazine.com/2016/01/create-customize-wordpress-child-theme/
http://op111.net/53/
http://vimeo.com/39023468

If the site you’re referring to is timchowltd.com – that is hosted on WordPress.com, where there is no access to theme files. You may add CSS styles via Custom CSS, which is available with the Premium or Business plans.

These forums are for folks running the WordPress software on their own hosting, not on WordPress.com. If you need further help with your theme on WordPress.com, feel free to post in the forums themes forum here:
https://en.forums.wordpress.com/forum/themes

Here are some tips on getting help in the WordPress.com forums: http://en.support.wordpress.com/getting-help-in-the-forums/

You can also access the live chat support option when available here:

https://wordpress.com/help/contact