SMTP Gateway for Workmail.

I'm trying to setup SMTP gateway for Workmail. I'm a novice with AWS. I'm pulling my hair out. I've looked at youtube videos and I can't figure it out. Everything I try, gives me the error that it can't find it. I have several staff that won't use the program unless they can go through Outlook or Thunderbird, so I need a way to link it. I've made a smtp in SES (user name and pw). I think it has to do with the name,address or port. ?? Thank you for the help. V