Unless it only has one long clip, your project will contain transitions. After you have two clips added to a project, there is a simple cut between the two. This transitions, or lack of one, is a powerful way to get from the first clip to the second. However, a cross dissolve or other transition may be the better option.
A cross dissolve is Final Cut Pros’ default transition. Fading through one clip into the next is a great way to soften the flow as you change from one shot to the next. In some cases, you may want a more complex transition. The Transition Browser contains a large selection for you to choose from.
Take a look at this quick tutorial to learn how to add a video transition, change the duration of a transition, select a new default transition, and what to do when you see the alert “There is not enough extra media beyond clip edges to create the transition.”
See how this compares to the previous version of Final Cut Pro with this older tutorial: