going to hybrid mode

2012r2 servers with exchange 2013 CU11 DAG

Looking to go hybrid and migrate some users to cloud.

• Not sure how to go about doing this, I do see the check box for it in the EAC.
• Can online user still use MS Outlook or just webmail?
• How will my DNS records be affected?
• What happens if the internet goes down but they are on the company LAN?
• How do they all co-exist?

Thanks in advance.