Rotate Projectile?

I currently have a fireball projectile that I've been working on. I got rid of gravity so it shoots in a straight line and a nice model for it. However, projectiles shoot like an arrow so the top of the fireball model is facing the same way the player was. How can I change the projectile's position? I tried going into the block bench and changing the direction in there, but it only worked partially. I also tried to use
"set rotation of target/entity yaw: pitch: " and even changed target/entity to source entity. However, it either breaks the fireball function completely. Or simply moves the player's camera and the target isn't being set to the fireball.