How to delete and re-install the demo theme to run live

Hey, Thanks.
I installed the SEO WP theme after purchase on
Howevor, I made an errow while installing the demo theme and seem to
have deleted the home page. I would like to delete the whole theme and
re-install so the whole demo theme can appear.
How do you go about with it.
How do you finally launch your theme after editing so the changes apply.

you could try a wordpress reset plugin

You can reset your website with: wordpress reset plugin, then install it again.