Back when I was XP focused such things were so easy. I was mobile then, and when moving into linux (debian) this was such a convoluted subject. You need to manually bridge the ports or find some ICS utility or run something like squid, I'm not familiar with everything. Quickly after that first look a few years back I built a crutch. I swapped a gsm mdem dongle for a standalone hotspot, a smartphone works too.. Then converted a router with dd-wrt to pick up that hidden hotspot and forward through it's hardwired eth ports. From there on out, just plug a system in, any system, and it automagically has internet. Depending on the router used you can have extra functions built in, monitoring, filtering, caching, almost a mini-squid. So extra stuff and extra complexity makes it easy.
Try not to ever make a machine dependent on another!