Add Progress bar into C# WPF App -- 2

It is very small task. I have very small C# WPF app which ready made and it receive food orders from a website. The C# app works fine but when I print the order it stuck for few seconds pulling the data from my server then it prints fine. I want to add progress bar while the printing process is busy. I need someone who has skills on C# WPF and APIs and php. I only need to add progress bar that's all