I am hopelessly provincial, have only been to London once as an adult, and took a black cab on the one journey I made while I was there.
Anyway, I will soon have to be there for five days, and get about the city using public transport.
Do I need an oyster card? Where do I get one?
Please treat me like an alien who knows nothing and explain it all in words of one syllable 
I am getting so chewed up and anxious about this it's unreal.
I basically have to go from Victoria to Waterloo and around Waterloo a bit, but I am SO worried about it that it is seriously starting to fuck up my chances of getting a really good job 
Please help