In the current preview versions of Microsoft Teams there is no option to stop the program from starting up when your computer reboots however, we can disable this process so that you can manually start the program up when you need to use it.
The Microsoft Virtual Academy now has a training course available to provide an introduction to Microsoft Teams and then information about deploying and managing the collaboration service for your organization.
Windows 10 has Cortana and Microsoft Teams has its own assistant in the form of T-Bot who can help you learn about the new team based collaboration service for Office 365.
A very big part of Microsoft Teams is the ability to have text based conversations in any channel of your teams site. These chats, depending on the subject and intensity of the disucssion, can get very lengthy so being able to mark a specific comment in that chat is an important feature and Microsoft Teams supports that capability.
If your team members are collaborating on a key document in Microsoft Teams then it is easy to add a Tab that contains just that document so it can be a focal point for the team.