I'm currently leaving the armed forces & looking to become a train driver what is the best way to start this application

Hi Anthony.
You would need to apply for a trainee train driver vacancy. All of our current vacancies can be found at https://careers.firstgroup.co.uk/jobs/search
Unfortunately, we don't currently have any trainee train driver opportunities, however if you register for job alerts at the bottom of that page, ensuring you select the job category as "Train Driver", then as soon as any train driver vacancies are advertised, you will receive an email notification. Should any of them be for trainees, then you will be able to submit an application.