How do I set traps (sprite) on random platform

hello,
I want to put traps on a random platform, but I'm a little stuck, I can do them appear but not on the platform: /
 
Thank you

I'm thinking you could actually set the platforms themselves to spawn the traps. Maybe you could have each platform generate a number on start of layout and if that number falls into a certain range a certain kind of trap is spawned along the platforms lowest y value at a random X value.

You could create a spawner sprite on each platform. Set them invisible. Then pick a random spawner and spawn your trap at that location.