Hey,
as Gregg said, there are prerequisites before you can do the Get/Checkout.
This is how we do it:
1) Accept TEE Eula (needs to be done, because we're using VSTS and not an on-premise TFS instance)
2) Create TFS Workspace
3) Create TFS Workfolder
4) TFS Get
Forgot the steps in the post deployment:
1) delete TFS Workspace
2) delay 10s
3) delete TFS Workfolder
best regards
Michael