Here are some examples:
* "Firstly, the weather was terrible. Secondly, the train was delayed."
* "I'm not going to that party. Firstly, I'm not feeling well. Secondly, I have to work tomorrow."
* "Here are the steps to make a cake: Firstly, preheat the oven. Secondly, mix the dry ingredients."
Key points:
* Use it to introduce the second point in a list.
* It is often paired with "firstly" or "first."
* It is used to add a second reason or argument.
Let me know if you have any other questions!