Can't get web mail on Office 365 Outlook.

I'm trying to set up my webmail on a brand new computer in Office 365's Outlook.  I've tried copying the same settings as my old computer, using the same settings as my android phone, and using IMAP (says certificate is bad) but nothing works.  My old computer is now SUPER SLOW, and I need to get this issue fixed ASAP, as this is my primary business address.