Here are the instructions to try it out yourself on the site:
1. Create an account here: https://www.pageblox.io/register.
2. Open a new tab, go to https://www.pageblox.io, then click the 'Try Now' button (must be on desktop).
3. Double-click on the screen to start commenting!
Show HN: Pageblox – React SDK for reviewing UX/UI changes in deployments
pageblox.io