The Library is where Camtasia's presets are kept. These include intro screens, outro screens, moving backgrounds, even license-free music tracks to provide a soundtrack. These can all be dragged directly on to your timeline.
If you aren't comfortable creating these or don't have the time to learn, this is one of the faster ways to incorporate high-quality production into your movies.
Icons are essentially emojis that can be dragged on screen. In the picture below, there are two icons (as noted by the timeline), "Woman 6," and "coffeethermos-01."
Intros are especially helpful, as they can offer a lot of movement and complex editing prefabricated for your use. Intros can still be customized and timed to your needs however this is a little more complex than we have time to get into. If you have questions about what is possible or would like some assistance, don't hesitate to reach out and I'll be happy to help.
Below is the "Ripples" intro, but remember that there are many other options:
Lower thirds are mostly used for introducing people onscreen (as unfortunately seen below), but can also be used to introduce specific pages or slides.
(actual graphics will be of a much higher quality than seen below. So will the content, assuredly)
Motion backgrounds can be used for title cards or as a segue between items.
Below is the "Classroom zoom" motion background, but there are other (mostly more abstract) options.
Music tracks (as well as other audio-only tracks) can be added to the timeline just like any other type of media.
In some cases (specifically when using the PC version of Camtasia) recorded video will appear as two separate tracks, one for audio and one for video.
Outros can be used to add a nice flourish to the end of your video. As always, they can be customized.