Responsiveness issues while publishing


I started using webflow 2 months ago for the first time as a conversion tool from Figma to HTML. After spending over 45 days going through tutorials, videos etc, I am still unable to deliver a proper website. I would like to know what are best practices to be followed, eg. basic unit settings, formats of images, the default desktop size to start with and defining custom breakpoints. Everything looks good in teh design mode. But upon publishing, everything shifts and some sections dont even show… some one please help!!!