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How to do it...

To create a digital clock, follow these steps:

Create a new Unity 2D project.
Import the provided Fonts folder.
In the Hierarchy panel, add a UI | Text game object to the scene named Text-clock.
Ensure that the Text-clock GameObject is selected in the Hierarchy panel. Now, in Inspector, ensure that the following properties are set:

- Text set to read as time goes here (this placeholder text will be replaced by the time when the scene is running)
- Font type set to Xolonium Bold
- Font Size set to 20
- Alignment set to horizontal and vertical center
- Horizontal and Vertical Overflow settings set to Overflow
- Color set to white

In the Rect Transform, click on the Anchor Presets square icon, which will result in the appearance of several rows and columns of preset position squares. Hold down Shift+Alt and click on the top and center column rows.
Create a folder named _Scripts and create a C# script class called ClockDigital in this new folder:

using UnityEngine; 
using System.Collections; 
using UnityEngine.UI; 
using System; 

public class ClockDigital : MonoBehaviour { 
  private Text textClock; 

  void Awake (){ 
    textClock = GetComponent<Text>(); 
  } 

  void Update (){ 
    DateTime time = DateTime.Now; 
    string hour = LeadingZero( time.Hour ); 
    string minute = LeadingZero( time.Minute ); 
    string second = LeadingZero( time.Second ); 

    textClock.text = hour + ":" + minute + ":" + 
 second; 
  } 

  string LeadingZero (int n){ 
     return n.ToString().PadLeft(2, '0'); 
  } 
}

Underscore prefix so items appear first in sequence

Since scripts and scenes are things that are most often accessed, prefixing their folder names with an underscore character, _as _Scenes and _Scripts, means they are always at the top in the Project panel.

Although the preceding code is useful for illustrating how to access the time component of a DateTime object individually, the Format(...) method of the String class can be used to format a DateTime object all in a single statement, for example, the preceding could be written more succinctly in a single statement:
String.Format("HH:mm:ss", DateTime.Now)
For more examples, see http://www.csharp-examples.net/string-format-datetime/.

Ensure the Text-clock GameObject is selected in the Hierarchy panel.
In the Inspector panel, add an instance of the ClockDigital script class as a component by clicking the Add Component button, selecting Scripts, and choosing the Clock Digital script class:

Add script components through drag and drop

Script components can also be added to GameObjects via drag and drop. For example, with the Text-clock GameObject selected in the Hierarchy panel, drag your ClockDigital script onto it to add an instance of this script class as a component to the Text-clock GameObject.

When you run the scene, you will now see a digital clock that shows hours, minutes, and seconds at the top-center part of the screen.