Anmelden hier:
https://login.microsoftonline.com

Infos:

https://support.office.com/de-de/article/anmelden-und-erste-schritte-mit-microsoft-teams-6723dc43-dbc0-46e6-af49-8a2d1c5cb937

https://products.office.com/de-de/microsoft-teams/group-chat-software?rtc=1&market=de

Download Teams:
https://products.office.com/de-de/microsoft-teams/download-app#desktopAppDownloadregion