Image foundry stack advanced

I’m trying to pass a variable $GET between two stacks.
Stack 1. Foundry stack image with in:

flag Add Link ->on
Edit link to the page 2 where I like to receive the value of variable.

In box of Set link:
I have test with put into the title of link page: page2?Variable=10020100
also used page2.php?Variable=10020100
In page 2: $course=$GET[Variable];

NO value is coming in page 2

In Box of Set link
Title: page 2 (link)
in custom attribute: Variable
in value 10020100

NO value is coming in page 2

But if aI make a direct call by button:
Variable 10020100 is coming in page2.

What I miss?
I didn’t find any information in manual, documentation, tutorial or knowledge base about it.
Can help me? is possible to pass this variable $_POST?

Thank you for your help in advance.


Are you missing the underscore : $_GET[Variable]

thank you for your advice.
Sorry for my writing mistake typing the message, you are right.
But I forget it into the message but not in the code.
The code is correct and run correctly if the variable is passing in direct way:

in page 2: