Guti_Grad

Hey folks, so I'm a Canadian B.Sc student at UBC graduating in May. Im looking to go into a masters (in Canada ideally) and I've already got a couple mentors in mind but for some reason I'm terrified of contacting them and don't even know where to start. I know it should be a pretty simple and straight-forward email, but I'm not too sure what to include. Was hoping you guys could give me some tips/pointers on what to email to prospective mentors. Also, what the hell is a writing sample? I'm honestly feeling very confused about the whole process so if y'all could give a man a hand it would be greatly appreciated!!!