I need help for my staff mod.

Use the summon mob procedure bock with the offset you want the mobs to be away from the player. An example with four mobs would be below. You could also use x and z instead of dx  and dz if you don’t care about the mobs being aligned with how the player is looking. 

On external call

Summon [mob] at dx + 2 y z

Summon [mob] at dx - 2 y z

Summon [mob] at x y dz + 2

Summon [mob] at x y dz - 2