first you go to your world ofc find a area to shoot the bomb
and then type this

/summon Fireball ~ ~3 ~ {ExplosionPower:0,direction:[1.0,0.0,0.0]}
it will summon a fire ball with the power of 0 and at the area at 1.0.0.0.0
if you want a bigger bomb change explosionpower:100 < to 100