Securing your pyro really is essential, and the best way to do so is via the staking method. Simply knock wooden or metal stakes into the ground with a mallet and then gaffa tape your fireworks to them.
You can also bury them; most fireworks have a bury line on the side to indicate how deep they should be placed.
If you cannot do this or don’t have stakes, then first of all I would advise buying some. If that’s not possible then you could also surround your firework with bricks to prevent them toppling over. If you wish to purchase stakes and tape, please see our firing equipment page.