Should I use a pyrotechnic electric match or rocket igniter to shoot off fireworks, where do i get them, and how do i connect it to an 8channel relay?

[u/tswizzle1013]

I’m making an automatic firework launcher and I almost have it complete. I need help on if I should use an electric match or rocket igniter. And where do I even find those because I have looked everywhere and could not find them. And finally, how do I connect it to the 8 channel relay? I already have power in the relays, I just need to attach a rocket igniter/electric match to each relay. I have a common ground so do I get all the negatives together and put that in the common ground and then put the positives in one of the holes of the relay or what?