I tried the block and it works for me.
First you must add the URL in the options in MT4.
Then in the block you can write delimiter, any single symbol, for example comma. Then you would expect the response from the server as comma-separated values. For example "value1,value2,value3".
Then when you get the answer, if you set the key to be 0, then "value1" will be read. If the key is 1, then "value2" will be read. And so on...