Overall process for me took over 7 months- very rigorous and difficult, but rewarding!
1) online application- standard stuff and you, your experiences and your motivations. Remember what you've said as it may come up at a later stage (final interview).
2) online tests- a bit challenging but nothing a bit of revision won't sort out. Logical, verbal and numerical reasoning.
3) video interview- tough, given between 30 and 60 seconds to answer a question that you have not seen before, eg Demonstrate when you have had high standards, What are you most proud of?
4) assessment day- challenging, requires you to have done a store walk before coming to the day, you must really know specific areas of the company and store layout, as we had to do a presentation (2 mins) on one of 6 aspects of the store/business. This was followed by reviewing some CV's and picking the right candidate for a position. It's okay to disagree with the other candidates there, but you all must come to the same conclusion eventually. You will be challenged by the person running the assessment day- stand strong but don't be arrogant or offensive. Be a team player but establish yourself as someone who can take charge when you need to. You will probably be nervous for this stage, but it's honestly not as bad as you may think !
5) final interview- this was with the MD, which is a very big deal and quite an honour to have an interview with someone so high up in the company. Be prepared for anything, including talking about your personal life. Be honest and don't come across as boastful, they really want to get to know YOU, not necessarily your achievements- at this stage, everyone is quite an impressive candidate. Don't try and be anything you're not, as this is for you as much as it is for them, and you must recognise if you're not the right fit- this is no reflection on your ability.
I found out within a few hours after my final interview that I got the job.
Good luck !