The transitional adverbs first, firstly, second, secondly, third, thirdly, last, lastly etc., indicate sequence or show the order in which ideas or facts are presented.
Note that firstly, secondly, lastly etc., are more formal than first, second etc., and are more common in British English than in American English.
Examples are given below.
- First, I support the construction of the shopping mall because it will create jobs. OR Firstly, I support the construction of the shopping mall because it will create jobs.
- First, you need to find a job. Second, you need to save some money. And third, you need to rent a flat.
- Firstly, you need to know whether you are financially capable of supporting a family. Secondly, you need to find out whether she loves you. And finally, you need to propose to her.
- So you want to get fit. Here are a few things you need to do. First, you have to stop smoking. Second, you have to get physically active. And third, you have to reduce your consumption of fatty foods.
Note that the expressions first, firstly etc., go at the beginning of a sentence and are usually separated by a comma.
The expressions in the first place, in the second place etc., can also be used with similar meanings.