In order to start to synchronize objects, you must have already created successfully an installation with at least an operation.
If you match this situation you will also notice that the installation is in "Pending" state in the dashboard and if you read the logs that already started to come from the agent, you see a log that say:
[WARN] The installation is in "PENDING" state, the agent will wait for a different state
So, in order to start the synchronization you have to enter in the installation page and click the button "Sync now" in the top-right corner, the button highlighted in red in the screenshot below.
A screenshot of the installation page with "Sync now" button highlighted
After successfully clicked the button, the agent installed in the server will start to run operation-by-operation after few seconds. To check the agent behavior and the operations progress, you can read the installation's logs updated almost in real-time.