Update launch_data_extraction.rst

Author: alan-tabore

docs/source/launch_data_extraction.rst

@@ -8,5 +8,9 @@ Store them in the same folder and:
 
 1. Click on the "Add file(s)" button of the data extraction dock
 2. Navigate to the folder containing your data
-3. Selected all your files
-4. Make sure that the file list becomes green (indicating the extraction was successful)
+3. Select all your files
+4. Click the "open" button. (your files should now be loaded)
+5. Check the box "has header" if the first line of your file is a header. (if you have multiple lines to skip at the beginning of your file, indicate the number of lines to skip in the entry box "Number of lines to skip".
+6. Indicate the delimiter of your data in the "Delimiter" entry box. If no delimiter is indicated, the default delimiter (a comma ",") will be used. The delimiter used in the example data files is a comma ",". The tab delimiter can be specified as "\t" or "tab"
+7. Click the extract button.
+8. Make sure that the file list becomes green (indicating the extraction was successful)