I wan to creat partitions for Linux?

I want to install linux on my laptop. The help tells me that I have to specify two partition for it. One for swap and one another for :/ . I have Windows on my laptop already and I want to install Linux beside Windows. The help tells me that I have to create two partitions on one drive. My question is that how can I do that when I am in Windows. I really do not want to lose my data on my drivers.