Create a new windows forms application project, then enter your project name is "MetroSplashScreen" and click OK button.
To make a metro form, you should install the metro framework by right-clicking on your project, then select Manage NuGet Packages, you need to search metro framework and install it on your project.
If you don't see the metro framework in your visual toolbox, you can view How to download and install metro framework
Drag the PictureBox, MetroProgressBar, MetroLabel to your windows forms application, then design a simple splash screen form as shown below.
To create a metro form, you need to create frmMain, frmSplashScreen form, then change inherit from Form to MetroForm as the following c# code.
public partial class frmSplashScreen : Form
public partial class frmSplashScreen : MetroFramework.Forms.MetroForm
Do the same way for the frmMain form.
Add code to handle your Main form as shown below allows you to call the SplashScreen form in new theard.
public partial class frmMain : MetroFramework.Forms.MetroForm
Thread t = new Thread(new ThreadStart(Loading));
for (int i = 0; i <= 1000; i++)
Thread.Sleep(10);//Only for demo
//Start splash screen
frmSplashScreen frm = new frmSplashScreen();
You can use Thread.Sleep method to delay process. in real world, your data will be processed there.