This is how to place a regular Tee and orient it in the direction you want.
Place a Rectangular duct (preferred view is Isometric)
Invoke the Rectangular Tee command and take it near the connection point of the duct and just type RR (it’s the shortcut key for rotate fitting) and then you get the desired opening to connect to and if your orientation is not correct then you can then press E (maybe two or more times) to get the desired orientation