1.Download and open the installation file. For the download you need to log in with your employee account.
You can find the installation file here: Sophos Endpoint Agent.

2. Click Install to start the installation. Old versions of Sophos and other security software will be removed automatically, if possible, as specified in the dialog.
Be advised Sophos Home Premium can not be removed by this installer. You need to uninstall it by yourself first and you might need to disable tamper protection in Sophos Home Premium before.

3. After the installation is complete, you will be prompted to reboot.