You normally do not need to create and edit LESS-files. Normally you just create a CSS-file called rt_acacia-custom.css (if you're using the Acacia template) into the template's css directory.
I edit that file on my computer with a code editor such as Sublime Text or Notepad++ and then upload the edited CSS-file to the template's css directory and then refresh my browser.
Please reply with a direct link to the issue & create a new thread for each new issue.
A template is only as good as the content that goes into it - DanG