Right then I will click the icon. But I have another question: During the install of Bitcoin Core it says you must have 450 GB at least (or whatever size at the time for a full download). Since I have never attempted to install it on a drive with less size than that and the size I want to use is just a small 100 GB HDD for this: will Bitcoin Core let me install anyway? Basically I only need the space required for the OS, a few extras and Bitcoin Core (the software not the blockchain) so im not even bothering with SSD.
Yes. It is simply a warning informing the user of the disk space requirements if you want the full blockchain, but there is no hard requirement that would make the software not run if it there isn't that much space available. Of course it will shut itself down if it actually runs out of disk space, but that's entirely different.