picking objects

i want to pick a gameobject in scene .how to do that plz help me in this.

please provide more information about what you want to achieve

There are so many objects in my scene. I want to pick one object store that as player game object variable .and I want to move that picked object using speed or time variables.

I can't understand you. If you want a object to move, u can do the graph on this object. If you want a reference you can do an object variable. What do you mean picking? You can use tags too.

Use a raycast from your camera to get the collier of the object, that got hit and get its game object. This you can write into your variable. 

Option A: Flow machines one every pickable object.

Option B: One Flow machine on a manager.