Setup to open a sus pdf

I received a mail in my Gmail account with a pdf attached to it. I am very curious to open it. What are the correct steps to guarantee my safety. Some thing I already have considered are:

1. Boot up a Linux instance in live mode.
2. Inside the live mode load a VM.
3. Connect my VM to my guest network on my home router.
4. Forward the gmail to a new account made specifically for that.
5. Log into the new Gmail from the VM.
6. Open the pdf.

Anything else? Or something I haven't considered?