Random objects in coordinates specific

how I make appear random objects at the coordinates -0.9 and 0.9.

My idea is to make objects appear randomly but only at the coordinates I mentioned above, I want them to appear only on these positions.

the attached image is an example of what I want.
Sorry for my english, i speak spanish.

how I make appear random objects at the coordinates -0.9 and 0.9

Suppose you have an array of prefabs, instantiate them randomly and place them in the required position. This is what you need to learn: