Hi there, I’m sorry to hear this wasn’t working for you!
When writing a post or a page with the block editor, you should see a series of buttons at the very top of the page: Save Draft, Preview, and Publish. These will appear once you start typing text into your post or page.
When writing a new page on your site, are you able to see these buttons? If not, has this always been the case since installing Gutenberg, or did this start recently?