How can I sandbox safely

I just got hired at an organisation and they are openinng attachments on the desktop as they say that the antivirus will catch it.
On my past organisation we used Triage.
It was a tool that could spin up a virtual machine in the browser then I would just drag the attachment right into it.
Now the question is, what is the most secure way to analyse a file? I know about any run but there the website owners are …

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