To select a device from the application database, simply select it from the DB devices list in the Device Tab (1). If the device you want is not in this list you can create it by going to Settings > MIB Settings > Devices. For more information on adding a device, go to article Configuring Devices.
Alternately, you can create an instant device by clicking the Instant device button (2). You need to enter IP address and SNMP community string. Instant devices have SNMPv2c and SNMP port 161.
All instant devices you add will be added to the Instant device list (3).
Instant devices will not be saved to application database and they will be cleared after you log out. Current device is displayed in the Device in Use section of the Device panel.