Generate prefab at random location and various time intervals

I have a lightning prefab and want to generate them at completely random times (say 10-20 seconds) and random locations on a 500x500 plane. I am very new to Unity game-making and would appreciate some help with the script as I don't know where to go about this.

 

Here are some of the things you'll need:
https://docs.unity3d.com/Manual/InstantiatingPrefabs.html

https://docs.unity3d.com/ScriptReference/Random.Range.html

 

For the non-random part, this is what you should do:

Code (CSharp):

1. public int maxValue = value
2. //You decide what is the value you need
3. public GameObject inst
4.  
5. void Awake()
6. {
7.    Vector3 position;
8.    position.y = 0f;
9.    for (int i = 0, i < maxValue, i++)
10.       {
11.          Transform point = Instantiate(inst);
12.          point.localPosition = position;
13.          position.x = (i * Vector3.forward)
14.          position.z = (i * Vector3.right)
15.       }
16. }
17.          

Or something like that Catlikecoding teaches something pretty similar to what you're asking in here: http://catlikecoding.com/unity/tutorials/basics/building-a-graph/

for the random part, is basically doing what https://docs.unity3d.com/ScriptReference/Random.Range.html says there in the script.

As far as the time go, you could use Time.deltaTime as a multiplier to the transform point. Now that's a shot in the dark, I have no idea whether that would work or not.