Select any network device from the ribbon by left clicking on it. The device drop down on the top ribbon, will respond to left and right click. But to select a device you will have to do left click only. 

The cursor will now show a small device icon attached to it.

Place a device by left clicking on the environment.

De-select a device by using the right click or using the escape key.

In order to connect two devices, you will have to select the link and then left click on one device, free the mouse button and then click on the second device and free the mouse button. Always click on the center of the Device. 

Clicking on the device name will not work. Performing a double click will throw an error. Clicking and dragging without freeing the mouse pointer would displace the device in the environment. The wired links may disappear if you right-click anywhere in the Environment. 

To connect wired node and switch use wired link whereas to connect wireless node and access point use the wireless link.  

To remove a device, right-click and remove connections to and from the device and then right click on the device and remove it.  

Click and drop Application to generate traffic. To generate multiple applications use the add button available in Application -> Properties. Configure Applications by right-clicking on it and setting properties.

Enable packet trace or/and event trace for packet log or/and event log details (optional).  

Enable dynamic metrics to monitor the value of a parameter over simulation time (optional).  

Click Run Simulation and set the simulation time to simulate.  

To get detailed help on Internetworks, please refer NetSim Help file-> Running Simulation via GUI.