One of the many things that Kantu dose great is the Info for this command button next to the command selector (I think I have almost read all of the entries).
However, the reason that your command is failing is that you have stored hello inside of the string https://www.google.com/ and the if command it trying to check variable ${url} which dose not exist in your example.
What admin was trying to show you was was how you store things so if you want to store a URL inside the URL variable, you must type in the value that you want inside of your variable into the Target field and the variable name into the Value.
I.e. Command | Store Target | Where you wish to go / store (in this case https://www.google.com) Value | Variable name (in this case the word URL)