New Microsoft Teams is just AWESOME, quick but useful post below shows how you have this preview feature to make your life EASY!
Open Microsoft Teams admin center [Ask admin in your organization if you don't have access] and follow path Teams > Teams update policies > Click on an existing policy or Create New > follow step 1 and step 2 below.
Toggle Try the new teams to get yourself into NEW TEAMS world, you may chose to go back to classic (GA) version at any point of time.
