how do you use the
/execute command? it seems dumb. I tried to use it for something, but the commands work exactly the same
The execute command is used to call a command on a specific entity.
execute <entity> <x> <y> <z> <command …>
An example would be if you wanted to strike all zombies with lightning you could use:
execute @e[type=Zombie] ~ ~ ~ summon LightningBolt
So as you can see you can use it to spawn things near entities.