Having trouble with GUI box

Hey Guys, I am having trouble with displaying text, I am using text from a text file.I just want it to display the text at the bottom middle of the screen. Please have a look, any help is appreciated.

 using UnityEngine;
 using System.Collections;
 
 public class npc_Dialog : MonoBehaviour {
     
     public TextAsset textFile;
     string[] dialogLines;
     bool bShowGUI = false;
     string dialog;
     
     // Use this for initialization
     void Start () {
 
         if(textFile != null){
 
             dialogLines = ( textFile.text.Split( '\n' ) );
         }
     }
     void OnTriggerEnter2D (Collider2D other){
                         bShowGUI = true;
     }
     void OnTriggerExit2D (Collider2D other) {
         bShowGUI = false;
     }
     void OnGUI(){
         if (bShowGUI) {
             if (GUI.Button (new Rect (10, 10, 100, 30), "Investigate")) {
                 Debug.Log ("You pressed the button");
                 Debug.Log(dialogLines[0]);
                 
                 GUI.Box(new Rect (30, 30, 100, 100), dialogLines[0]);
                 
             }
         }
     }
 }