What makes you think that? Their website has instructions for installation via a Linux box. https://www.ventoy.net/en/doc_start.html

Adding on to other suggestions, if you’re not aware of Ventoy it’s a very handy tool. Using it you can have a USB drive with several live images on it which you can choose at boot time. Great for quick testing, just drop an ISO in a folder!

It’s called CIDR notation, the number represents how many bits of the whole address represent the “network” part of the address. /8 is equivalent to a subnet mask of 255.0.0.0