downstroke and upstroke

I have recently purchased and started learning Snow. Everything is going well, but I find that the sound made by my downstroke is inconsistent. What is the proper technique for downstroking? Do you put your thumb and finger together as if holding a pick and strum down? do you strum the strings with just 1 finger? multiple?
Also, I have seen people strum up and down somewhat rapidly with their fingers, and I was wondering how they do that. I know that the downstroke is played with the nail, but is the upstroke also played with the nail? or is it the pads of your fingers?
Just a little clarification would be nice. Thanks!

EDIT: Whoops read your post wreong, sorry
Flamenco technique (used in playing spanish acoustic guitar)

That is called flamenco for future reference

I didn't purchase the lesson so I may not be doing it correctly, but I play the strumming part like i play the regular finger plucking one, only I pluck 2 strings with 1 finger.
There are many ways you can get that sound...not sure how it goes in snow :S
If it's flamenco style I definetly wasn't doing that O.o

oh sorry i didn't know its called flamenco style. my bad. how is that done?