As above 
Travelling to central London for a night out on Saturday and considering getting a blow dry when I arrive as I am truly rubbish with hair.
Seems easy enough to book online, but some places seem to have set styles - do I see pictures and choose when I get there? Do you go with dirty hair and they clean and dry it? Do they put product in at the end so your hair stays looking great or do I need to take my own? Can you get hair up or a braid instead?
Basically, please explain blow dry bars as if I were 5, from another planet and have never seen hair before! 