For 'real flint and steel' (or a pretty hard rock and steel), I needed a lot of practice, it's not necessairly intutitive on where the spark is going the first few times, or how to hold and strike so you get the best results.
It's pretty easy to wack your fingers, and you clearly need eye protection.
Getting sparks is not a difficult task, but making fire assumes you have a good tender pile in place before you start. This is where I think most people have the more difficult time.
For the firesteel / firestick types of products, I found these to be very easy to use.
First, make sure you have a very dry very fine tender pile that is large enough to catch the sparks. Something the size of an 8 oz cup works for me. Very dry, and as fine a material as you can find (small twigs may be too big, but if you shave these down, that can work)
Next scrape off some of the firestick material onto the tender pile, if you're not sure how much, 10-12 scrapes should work, but you have to do this relatively slowly to keep from generating sparks.
Once you have the tender pile ready to catch sparks, build the kindling around it, and build up from there. Make sure you have access to the tender pile.
Last part is to start striking / scraping fast with a knife or other appropriate scraper. This is much easier than flint. You can get pretty good fairly quickly, getting a shower of very hot sparks that will ignite most any dry tender, and the direction of the sparks is very aimable.
You should be getting a very nice shower of very hot metal going onto your DRY TENDER, that can ignite by itself or with a little blowing.
From there, just build it up.
Much safer than rocks, and much faster than making a fire bow (aka rubbing sticks).
If you're going to try flint and steel, please wear eye protection!
Hope that helps,
MikeB