How do i connect my asas nimbustor NAs via Proton VPN?

[NickSibley]

I have an ASUS Nimbustor AS5304T-4B46 NAS. Recently a hacker managed to access my system tried to ransom me but when i refused and deleted the file some how he/she managed to access my NAS and wipe the entire contents. Everything gone. so i now have reformatted al lthe disks.
I have alsos taken out a PROTON VPN Plus subscription to cover my laptop, my two other HomeTheatre PCS and the ASUS NAS.
But how do i install the VPN onto the Asustor NAS?
I dont see or not being pc literate enough, know how to download the Proton App as the donwloads offered are for Windows, Apple IOS and Android systems.
Do i use any of these or does the Asustor NAS have its own VPN i use?
Sorry bit thick and confused here?
Any help much appreciated
Nick