Or you can do it via staging if your hosting gives you that option (we have it on our SiteGround hosting), or you have such staging plugin:
[https://www.wpbeginner.com/wp-tutorials/how-to-create-staging-environment-for-a-wordpress-site/](https://www.wpbeginner.com/wp-tutorials/how-to-create-staging-environment-for-a-wordpress-site/)
After site is finished you can just “push” it to live.
Oh, by the way, are you working on it yourself or do you want to have it made by someone else?
Backup live site
Import backup to a local dev environment
Change theme on local
Adjust theme
Backup local site with new theme
Import backup to live site
Profit?
If your hosting offers a staging environment, you could use that too.
Don’t forget to backup the current site anyway.
For local dev you can use LocalWP
All the best, let us know how it goes
You can check out the following links for properly changing the theme:
[https://www.wpbeginner.com/beginners-guide/how-to-properly-change-a-wordpress-theme/](https://www.wpbeginner.com/beginners-guide/how-to-properly-change-a-wordpress-theme/)
[https://www.wpbeginner.com/beginners-guide/checklist-15-things-you-must-do-before-changing-wordpress-themes/](https://www.wpbeginner.com/beginners-guide/checklist-15-things-you-must-do-before-changing-wordpress-themes/)
[https://www.wpbeginner.com/beginners-guide/what-happens-when-you-switch-your-wordpress-theme/](https://www.wpbeginner.com/beginners-guide/what-happens-when-you-switch-your-wordpress-theme/).
You can redesign your site, in a way to try different themes offline, then switch to the new site when you’re happy with it:
[https://www.wpbeginner.com/wp-tutorials/how-to-create-a-local-wordpress-site-using-xampp/](https://www.wpbeginner.com/wp-tutorials/how-to-create-a-local-wordpress-site-using-xampp/)
[https://www.wpbeginner.com/wp-tutorials/how-to-install-wordpress-on-your-windows-computer-using-wamp/](https://www.wpbeginner.com/wp-tutorials/how-to-install-wordpress-on-your-windows-computer-using-wamp/)
[https://www.wpbeginner.com/wp-tutorials/how-to-install-wordpress-locally-on-mac-using-mamp/](https://www.wpbeginner.com/wp-tutorials/how-to-install-wordpress-locally-on-mac-using-mamp/)
After the site is finished you can migrate it to live, it’s simple with migration plugins, see them here:
[https://www.wpbeginner.com/showcase/best-wordpress-migration-plugins-compared/](https://www.wpbeginner.com/showcase/best-wordpress-migration-plugins-compared/)
(PS We have been using All in one WP migration for that)
Or you can do it via staging if your hosting gives you that option (we have it on our SiteGround hosting), or you have such staging plugin:
[https://www.wpbeginner.com/wp-tutorials/how-to-create-staging-environment-for-a-wordpress-site/](https://www.wpbeginner.com/wp-tutorials/how-to-create-staging-environment-for-a-wordpress-site/)
After site is finished you can just “push” it to live.