Open your crafting menu
Gather gunpowder
Gather paper
Gather dye (for color) or optional additional dyes (for fade)
Make a firework star:
Place paper in the crafting grid
Place gunpowder
Add dye to change the firework star color
Create the firework rocket:
Place paper in the crafting grid
Place gunpowder
Place the firework star in the center (or as required by the recipe)
(Optional) Add additional gunpowder and/or additional stars in compatible crafting patterns to increase effects
(Optional) Add a firework charge:
Craft a firework rocket with the desired effects, then use it in a dispenser or hand
(Optional) Use a dispenser:
Place a dispenser facing where you want the rocket to launch
Put the firework rocket into the dispenser
Power the dispenser with redstone
(Optional) Use a crossbow:
Load the crossbow with a firework rocket
Fire to launch the rocket