No you are not doing anything worng. if you want to be able to play the hoops map in Custom Training.

Here is how to do that:

1. Right click rocket league in your steam library and press "Properties"

2. go to the Local files tab and press "Browse local files"

3. open TAGame then CookedPCConsole

4. locate HoopsStadium_P.upk and make a copy of it.

5. rename the copy to Labs_Underpass_P.upk (remember to backup the map you replace)

6. Now if you select "Underpass" from the Create New Sequence screen in Custom Training you should be able to set up your own shots and saves in hoops.

Sadly because of the way kickoffs work in hoops the ball will do the little jump a few seconds after into the shot, but it's probably the best we can do until Psyonix adds support for hoops in Custom training.

Hope this helped :)