Planner / Tasks not Available in MS Teams Apps

Hello, 

i have a problem with the MS Planner app / MS Tasks / MS To Do app. 

I am a little bit confused about the names of the app, but I want to use the "To Do" App in MS Teams. 

I have a Business Standard Licence for Teams but the To Do/Planner/Tasks App ist not available. I can't find the app and so I am not able to add the app to my teams. 

In the Microsoft Teams admin center -> Teams Apps -> Manage Apps, the app ist not available too. 

Any ideas? Thanks in advance.