Download the latest stable Agent:
If you execute the Installer without any parameters, a wizard will guide you through the Installation. This is the recommended way for your first Agent installation.
Later you will probably install the Agent in unattended mode. This can be done with the
/S parameter (Uppercase S for silent installation).
In bigger Environments, you probably prefer to rollout the Agent with a Group Policy.
The Agent is creating the hardware Object in the CMDB. A few minutes after installation you should see your hardware.
A few minutes after a new installation the Agent is fetching Inventory and Windows Update statistics. This would be visualized in the Update Center