The three most popular first aid training courses are Emergency First Aid at Work (1-day), First Aid at Work (3-days) and Paediatric First Aid (2-days). What training you choose depends on the environment that you work in and who you work with.
For example, if you work in a high-risk environment, like a construction site, you will require the 3-day First Aid at Work training. In the same way, if you work with children, you will need the paediatric first aid. It is best to speak with your employer to identify the kind of training required.