They must have had a primitive version of tanneries.
There would have to be a secure space where the bones and a hides could dry out, without any hungry animals trying to eat or chew them. The aroma of new blood and freshly torn flesh would advertise the location of that secure space.
Maybe there was a form of Cave Man sentry posted. Someone standing by with a pile of rocks to throw at any approaching beast.
“I think this shows that Neanderthals really knew what they were doing”
Undoubtedly.
Nobody could push a bone across skin like good old Og.
Did they go and get the leather at Tandy Leather? Leathermaking, so simple even a caveman can do it...
Alas, poor Auroch...