You can start a free trial here anytime you want. As Content Sync sits between your sites, we need HTTP / REST access to your sites so you can’t run Content Sync in a local development environment, unfortunately. Instead, please use one of your dev/test/stage/QA environments that are publicly accessible (or protected by Basic Auth). Alternatively, you can also use a cloud IDE like Gitpod to have a dev environment that Content Sync can also access from the outside.
If you struggle at any point just reach out to our support in the chat or through our ticketing system here.