How to validate document uploading using file picker?

I want my user to upload a file, but I want it to be mandatory my user should not move ahead without uploading any document.
How do I achieve this?
@Ritik_Dixit Can you answer this?

  1. File Upload Field: Drag and drop the file upload field onto your user interface where users can upload files. This field allows users to select files from their device.
  2. File Picker Task: Set up the file picker task to enable users to pick the file they want to upload. This task should allow users to browse their device and select the desired file.


  1. Select Relevant Entity: Within the file picker task, provide an option for users to select the relevant entity where the uploaded file will be stored.

  2. Navigation Button: Drag and drop a button onto your user interface. This button will serve as the control for users to navigate to another screen once the conditions are met.

  3. Business Rule (BR): Create a business rule to restrict user navigation until the relevant entity is not empty. Follow these steps to create the BR:
    a. Define the condition of the BR: Entity != Static("", string). This condition compares the selected entity to an empty string.
    b. Set up the BR action: If the condition is met (i.e., the selected entity is not empty), allow navigation to the destination screen. If the condition fails (i.e., the selected entity is empty), prevent navigation to the destination screen.

  4. Implement Conditional Navigation: Configure the navigation task associated with the navigation button. Make sure that the navigation task is only triggered when the BR condition is satisfied (i.e., when the selected entity is not empty).