How to download and install over a compromised network

i share a internet with my parents, who have had several viruses and scares in the past. obviously i cant change my living situation and share a internet connection with them.

im worrier that our internet is already compromised. how would i assure that the qubes os i download hasnt been compromised?

I know i would have to verify the install, i can do that, but is there any additional steps i can do to be absolutely sure that wheb i install qubes its a legitmate install.

for example is there a way to check within qubes that the signature is correct etc.

also, is there anywhere i could purchase a securely made usb / cd for qubes? since my other devices onvmy betwork could potentially be compromised.

I think that signature check Verifying signatures | Qubes OS is enough.

See also: Frequently asked questions (FAQ) | Qubes OS