Trigger for people joining

OS Name/Version: Ubuntu

Product Name/Version: Bedrock

Problem Description: Trigger userID and user

Steps to reproduce:

  • Step 1 Added trigger
  • Step 2 added information
  • Step 3 Googled the difference

Actions taken to resolve so far: tried the same name in both slots

I am trying to add a trigger to get a notification when people join the server the only thing i need help with is its asking me to use a variable the user and userID i dont understand the differance and if i figure it out do i keep the @ symbol. Thank you

This is what is says

This task failed the last time it ran:

The value cannot be an empty string. (Parameter ‘from’)