Without a doubt the most popular piece of prepper gear for starting survival fires is the magnesium fire starter. Also known as a firesteel or ferro rod, this simple device emits hot sparks to catch tinder on fire and almost every prepper packs one in their bug out bag, at least as a backup. The compactness and low cost of these ferrocerium sticks is the reason for their widespread use. Other viable options for survival starting equipment include the Fire Piston (or slam rod), and Solar Fire Starters.
How to use a magnesium fire starter is simple. Just take your survival knife (or other piece of metal) and strike the ferro rod to produce sparks. When the 5000 F sparks land on dry tinder you've prepared earlier, just blow on the embers to get the fire going. Then continue using your bushcraft skills, to transfer your starter fire to successively larger chunks of wood. It is almost as simple as striking a match.
But know that the ferro rod material does wear away with each fire you start. Many will last over 10,000 strikes before wearing out, but eventually will have to be replaced. And the low price of these means you can afford to buy quite a few to stock your prepper bug-out bag - which is just what I would do. Overall the simplicity of the magnesium fire starter makes it a winner for preppers and survivalists alike.