Hi!
Tempo sync is currently only available in the latest beta. You will not be able to use it in the v0.3 version of the plugin.
(check the lower left corner of the plugin UI to confirm which version you are running)
If you want to try it you can read more about the beta here:
https://daniel-gergely.itch.io/emergence/devlog/374600/emergence-v10-beta-available