A number of ways and most are fundamental to NL editing. Some depends where you are “getting” the new clip from. eg ,. Source Window or Project Window.
Heres a couple of ways:
Drag a new clip into a timeline position using a modifier key – in this case “CTRL”
You can insert your clip using Insert Command or Insert Keys or Insert shortcuts eg “,”
Note that inserting usually requires that you set the track as the “Target”