To connect devices to a junction box, go to
Ribbon: DM Electrical->Devices-> 
Add Device to Junction Box
Pulldown Menu: DM Electrical->Junction Boxes->Add Device to Junction Box
You will be prompted to select the junction box.
Select junction box:
You will then be prompted to select the devices you want to associate with the junction box.
Select objects:
The selected junction box and devices are now associated with each other. When loops are drawn using the Draw Homerun and Loops command, these devices will be directly connected to the junction box. The junction box will be connected to other devices on the circuit. Nothing else will be connected to the devices.
If the device was previously connected to a different junction box, it will now be connected to this junction box. You do not need to disconnect the device from the old junction box before connecting it to a new junction box.
Although the drawing indicates the junction box and devices are associated by the loops drawn, the devices have not been circuited. You still need to connect the devices to the appropriate circuit.