Office Group creation best practices in hybrid environment

Sorry that was rather vague, I am a little new to this process. When adding a new person for the first time. I was also wondering, if you add someone new for the first time, do you have to add them both on premise in AD and manually add them to groups that they would be a part of every time? 

We have a Hybrid environment with all on premise distribution groups that we would like to migrate to Office 365 Groups so we can use teams.