There are several ways to add transitions into your Sequence. The easiest method is to select the end point of a clip, so that it is highlighted.
Then either press ⌘ T or double click on the end point and an option Add Transition "Cross Dissolve" will appear. Cross Dissolve is typically the Default transition, but you can change the default in the Effects tab of the Browser.
To select a specifc transition, you can use the Effects tab of the Browser to search for a transition.
Once you have selected the transition, simply drag and drop on the end point of the clip you want. To edit the transition, simply double click and it will appear in your Viewer.
Whether you want captions, labels, titles or credits, text is often the biggest question for budding filmmakers. Follow these steps to add in text.