Its pretty darned easy Damocles,
I used to make flint arrowheads and knives when I was a kid-Its sort of built into us,from ages past.I didn't have any real training and i was just a
kid,but i found it very effective to get a big chunk of flint and (covering eyes!) smash it with another rock-the resultant shards would be effective
to make all manner of items.Fishing,hunting,blade type items.
Its one of those things that may at first sound tricky,but once you give it a go it feels pretty easy.
I know professional knapping is a real skill,but its amazing what you can do just messing around,with a bit of determination.
Problem is,flint is just too sharp sometimes-its really easy to cut your fingers without realizing for a while.
You can also make horrid anti personnel/horse/car caltrops with flint spikes.
Shards may be used to booby trap climbing ropes,car door handles,switches,gates etc.
Flint shards can be easily serrated by use of another bit of flint,to make a good saw,for wood or meat.
Plant flint spikes into cement on wall tops where its illegal to use glass!(its better than glass anyway).A good vandal/burglar deterrent.
Flint powder is incredibly bad to breathe in and get in your eyes as well so in a worst case scenario this could have survival/defense
All of the above is totally hypothetical of course,and I would never endorse,encourage or recommend its use by anyone until after the apocalypse.