Windows 3.1 is NOT to be downloaded "legally". Abandonware literally means Abandoned software. I'm sure Microsoft won't be too happy if you ask them for a 'legal' download. The only legal way to get a copy of Microsoft Windows Version 3.10 is if you bought a retail copy from your local store back when it still was on shelves.
Literally no one cares where a person gets their Win3.11 copy from nowadays, but I'm sorry, you can't get a legal copy, you couldn't get one for like, the last two decades, that's literally why it's abandonware.
Edit: I just realized, I sound angry or mad or something, sorry for that.