On a separate pc you'll need to download the media creation tool and use it to burn windows to either DVD or flash drive. (recommend 8Gb minimum). From there you plug those into your pc and have bios set boot priority as either uefi USB or uefi optical first, which will then boot from your media, not the HDD. This'll bring up the option to install several different versions of Windows. (10 Home 32bit, 10 Pro 64bit etc) you choose the one you had prior as that's what the key Microsoft has recorded for your pc.
If you already have a copy of Windows to install, you just need to boot into bios and change the boot order to your media first, then the hdd second. Right now it looks like the hdd is first, so won't boot.