Could you let us know which method have you adopted from the above suggested ?
If Write Cell Activity is your preferred method, then similarly you would need to use two more Write Cell Activities to write the data you want to write, specifying "B"+(DT.Rows.Count+2).ToString in the Cell Range Property for writing the Date value in Column B and "C"+(DT.Rows.Count+2).ToString for writing the value Executed successfully.
Let us know if you still need help.