This is about how to use the Send Box feature of the PokGear app.
This method support up to 11.0, the current update of 2/3DS
Before you start, you need to Install the PokGear Box Receiver into your 2/3DS.
Prepare a Box
Click the Send Box button
Choose pokemon to put into a box
Click the Send button at the upper right corner
Receive them by runing PokGear Box Receiver
The pokemon will go to the Box 1 of the pc in game and replace the current pokemon in there. So you may need to move the pokemon in Box 1 to other Box if you don't want to lose them.