Make sure you have followed the basic setup instructions on the Getting Started Page before proceeding to Step 2.
Make sure the Settings tab of the EveryTick spreadsheet has the SierraChart directory accurately set to C:\SierraChart\Data\.
Make up a Text symbol and enter it into Column 1 of the "Write" sheet. Be careful not to use any existing symbols that trade on any exchanges. To be safe, you might want to include a number in the symbol you make up. For instance AAPL1 is sure not to interfere with AAPL. Now enter a DDE or RTD subscription code into Column 2. For instance, for IQFeed, the DDE format is =IQLINK|AAPL!Last or IQLINK=|AAPL!Volume. Then press "Start."
Open SierraChart and go to File→Open Intraday Chart (Ctrl-I). Then select the your new Symbol from the directory (Note that it will have a .SCID file extension). The chart will be updating in Real Time.