How To 'Work Behind the Scenes' Prior to Publishing

Hi
Apologies if this has been answered before, must be not googling correctly.

Wanting to change my current them to Sydney, have 11 years of work on wordpress blog.
How do I do all the redesigning (privately), prior to publishing?
Much Thanks
Erin

Dear Erin,

Thank you for reaching out to us here.

You can run WordPress locally on your PC/Mac. Please follow the instructions on WordPress codex:

Once you’re done designing and want to move your site on your live server, follow this comprehensive tutorial.

Regards,
Kharis

Kharis
Thank you, admit I’m rather intimidated looking at that codex, I’ll keep studying it.
Thank you.