Did you press the Publish button and got a nice big pink spinner and Open website button? Looks like your site wasn't published, maybe you stopped at the preview screen? 

 I published 2 sites. Now just want to change the theme an existing subdomain. 

 Can i change the theme of https://techjunkie.npub.pro ? 

 Go to admin section of the site and click Theme settings then Switch theme at https://npub.pro/admin/naddr1qqghgetrdp482mntd9jn5dmyvv6xyvszyzndn7npgtegprljlr79v7vk49pgq52np7w73qqu2kdkj8g2h5g7wqcyqqq8wvq076je5/dashboard 

 Awesome!