Are you looking how to get their emails from AngelList? I have used AngelList for lead generation, it works very very well. You need some additional tools to locate their email address. You can use hunter.io and anymailfinder. All you need is a name and their website domain and it will locate the email address. Alex Berman does some great videos about it.
https://www.youtube.com/watch?v=3oqPBL-4Rrc