It really depends on how complex your game is.
Depending on your specific implementation, it can vary from “display button layout in the loading screen” to something that actually requires effort.
Whatever you do, I suggest a silent tutorial: Feed the player enemies that don’t shoot, then let one of those first few enemies drop an upgrade (if that’s a feature you have), then create a situation where the player has to go through a tight passage so that they learn what the hitbox of their vehicle is.
Hitboxes in Danmaku can be quite unintuitive. If yours is much larger or smaller than the player model, you definitely need to teach players early how big the hitbox is.
Remember, the best tutorials do not look like tutorials and have no on-screen prompts. They just throw you into the game and make it so that you learn everything just by paying attention to the first part of the game.