Exchange Office 365

I think you need to provide a little more context here. Are you trying to connect Outlook 2016 to Office 365 or are you trying to connect it to on prem exchange? If you are trying to connect Outlook to Office 365, there are any number of tutorials out there like this one.

https://oit.colorado.edu/tutorial/office-365-outlook-windows-manual-exchange-configuration

Hi, Jeff so we have users who use office 365 and my current job we are going from a hosted exchange server at a data center to exchange online.  We have seen people who use outlook 2016 with office 365 are connecting to our new server.  We don't want them to connect to the new server yet.  I was wondering if there was a way in office 2016 to connect them to our old server when we configure outlook.

How can the users with Outlook 2016 connect to Office 365 (Exchange Online) unless you have migrated their mailbox there already? Your Autodiscover records in the domain  should still be pointing them to the Hosted exchange server until you are ready to have them move. Teh users may be using the new Simplified Account Creation Wizard (Connect Outlook to Office 365) that comes with Outlook 2016.
  If you need to turn-off the Wizard, you need to disable it in the registry, either manually or via GPO.
 You add the 32 bit Dword value of DisableOffice365SimplifiedAccountCreation  to HKCU\Software\Policies\Microsoft\Office\16.0\Outlook\setup and give it a value of 1.

Hi, Jeff so the new exchange server is turned on but the users have not been migrated to the new server.  For some reason when they open their outlook it will automatically connect to the new server.  I have also seen that when we are trying to create new profiles using the mail wizard that it will connect to the old server sometime.

When you say the new Exchange server, you mean Office 365? Exchange Online?

What i mean is when an end user has there outlook open itis connected to the correct exchange server but then will connect to our exchange online server for no reason.  It only happens to outlook users who are on office 365

Than you for the help.