Template and theme mod online?

Well, I would never experiment on a live site with that damned online Theme Editor.
– you have to make your blog vulnerable = world writable files = open for hacking
– there isn’t an UNDO button!

Theme design should happen on your computer.
However, downloading WP doesn’t mean you can see it on your computer. You need XAMPP or something similar to make your machine a local server, otherwise you cannot “see” the .php files (I mean how do they look like rendered).

Ok, that makes sense. Given the vertical learning curve here, would it be easier to try and find someone to attempt or reality check the design for me? I prefer to learn how, but this looks ambitious.

Maybe you want to read some documentation about WP design:
Theme_Development
Blog_Design_and_Layout

That’s actually what got me started thinking I could do it, great support & guide info. I’m just wondering whether trying to learn XAMPP on top is unrealistic.

There is nothing to “learn” about XAMPP.
https://www.apachefriends.org/en/xampp.html
You just download and click the install.
more: https://www.tamba2.org.uk/wordpress/xampp/

The advantage of it being: you can see “in live” all your edits instantly.

Wow, look how much I’ve learned already ??

Another block of ignorance to knock down for me – if I go this route do I need Ftp to upload? And is there any issue uploading from WP desktop to WP online?

You ALWAYS need ftp – how else do you move files between your computer and the host server?

Don’t mix unrelated things ??

Thanks moshu. At the bottom of a waterfall all you can see is noise. Recommended ftp download?

Filezilla – it’s free and works very well.