As you can see after start of the the application klogic, you can select different types of devices
in the toolbar.
Alternatively you can choose a device from the Menu "Logic".
After choosen a device you can drop it on an empty place on the screen.
Usually you can choose between the following functions:
properties | display device properties | hide draph | hide device in the simulation graph | show graph | show device in the simulation graph | open | display content of the subcircuit | open in window | display content of the subcircuit in a new window | display graph | display content of the subcircuit in the simulation graph | remove | remove the device |