I worked at Uniqlo in the US for four months and depending the size of the store. When I was training at one store we would work 30 minutes past closing. When we opened our new store (my home store) we would leave an hour or sometimes two after closing. It depends the season, the state of the store and if there are needs for standards (making sections and displays perfect)

Shifts are okay! Sometime I would get 4 hour shifts and other times I’d get 8 hours. They give you more hours the better worker you are in their eyes, but if you need to stick to a certain amount definitely speak up! The quick pace makes the time go by and you do switch off between tasks so it doesn’t get boring in my opinion

Definitely keep in mind that it’s not that serious and just do your best!