Do you have a url we can look at?

my test site is mrkitwindows.co.uk. Been using mod designer to create and experiment with creating a new theme call theme designer.

thanks

You need to target the list with some CSS to change it's formatting. There are several ways to approach it which depend on exactly how you need it to work, but this is a basic way of doing it:

Look at your source code, you have unclosed elements in the header. I’ll assume it’s the nav template you’re using. You can’t use the ‘Responsive Header Navigation’ template with your custom theme.

Is 'wrapper' supposed to 'wrap' the main page content, it's not?

Why use ‘Bootstrap.css’, A newer version is included with C5?

Why call so many css and js files.

CSS files can all be called from the themes ‘default’ less file.

Some js files are not being used?

i followed the tutorial for the sailor theme, it came from bootstrapmade.com, i am currently learning how to make a theme using the theme designer mod.
I know i have ton to learn yet, remove unawanted js files, combine css files etc.
i will try your tips, thanks.

any help is greatly wanted and received thanks

I use
" display: block;" to let the links appear in a line.

I recommend creating a special CSS-File only for the menu.