Uniform does take forever to arrive once they actually order it. So you will be told to wear plain coloured clothing mainly black to shifts. I think mine eventually came when one of the directors of the company came in store and asked where is my another colleagues uniform. Then all of sudden months of waiting uniform was now available.
Yes that is your first shift dont worry not having the uniform yet, they will order you one. For the time being wear all clean black with no stripes or any additional colouring. If you're still unsure contact your manager never be afraid to ask. It is better to ask rather than staying quiet and getting it wrong. Good luck and hope you enjoy your first shift
Ex trainee supervisor Mat from Altrincham Iceland