How To Put 2 Panel in 1 scene?

I make a menu
1.Panel Menu with start,about,exit (for main camera)
2.Panel Menu with About description (beside the first one )
in 1 scene
So the problem I don’t know script C# i put on About Button,to take panel about description in 1 scene???Can Help Me Please

The easiest way is to have a script, that has references to all your panels, to switch them on/off

using UnityEngine;

public class MenuNavigation : MonoBehaviour {
    public GameObject Panel1;
    public GameObject Panel2;

    public void showPanel1()
    {
        Panel2.SetActive(false);
        Panel1.SetActive(true);
    }

    public void showPanel2()
    {
        Panel1.SetActive(false);
        Panel2.SetActive(true);
    }
}

Just don’t forget to assign your two panels to this script. To link your buttons to the script, just click on the “+” symbol inside the On Click() section of your button, drag and drop the gameobject your have set this script to and choose in the dropdownmenu:
MenuNavigation → showPanel1 or showPanel2

One could make this more generic with an GameObject Array, but I think in your case this is the more appropriate answer.