In order to run a simulation in LTspice, you need to assign SPICE pins to component pins when creating a component. The SPICE pins to be assigned depend on the device type you select.

For example, when you specify "Q-Bipolar Junction Transistors" as the device type of a component, set "B" to the base pin, "C" to the collector pin, and "E" to the emitter pin respectively at the SPICE Pin Order column in the Pin tab of the component edit sheet.

For details on how to assign SPICE pins to component pins, see the Linking a LTspice Simulation Model to a Component page.

The SPICE pins to be assigned vary depending on the device type you choose. For details on each device type, refer to the Device Type page.