When I started wood carving, the only sharpening method I remembered was from seeing my mother use some kind of smooth broken stone that she passed over the length of the knife blade before sacrificing a chicken.
I also remember seeing my father use a very coarse stone wheel placed on a motor shaft which threw many sparks when he sharpened some large axe for splitting wood.
I had neither of those around anymore in my rented place in the city so I jumped headfirst in the mind numbing and sometimes esoteric art of getting a sharp blade.
They fortunately came with a strop, basically a plywood base in the form of a paddle, with leather stuck to it on both sides, and a green waxy bar. Unfortunately I had no idea what to do with it.
Stropping is, at the most basic level, dragging the blade back and forth on a semi-hard surface (like leather). Clean leather won’t make your blade sharper though, and that’s why you have that green bar which you need to rub onto the leather. It contains a fine abrasive that slowly removes tiny amounts of steel from the very tip of your blade to make it sharper.
And so on. It’s hard to find much exact science on this, everyone figures it out as they go, and experts share their beliefs based on their extensive experience.