iMovie is a video (..and audio..) editor. It's just a tool for assembling clips of video together.
When you've imagined what you want a finished video to look like (e.g; things spinning, enlarging, changing perspective, etc) you then have to work out which separate
tools you'll need to achieve each of those effects, or appearances.
So if some of your video is to include "screen capture" (i.e; bits of what appears on a computer screen) you'd need to find a particular tool which can record things straight from a computer screen ..a program like
Screen Record (click on that blue link) or
Snapz Pro, for example.
(..iMovie can't record what's on your computer screen, remember; it's just a tool for
assembling separate video sequences..)
A program like Final Cut Studio (..which costs much more than iMovie!..) lets you lay out video along several different 'tracks', and lets you manipulate the
perspective of each of those bits of video, using a component called '
Motion', so that one element can be turned sideways, say, while another clip comes up in front of it and can disappear into the 'distance' behind it. iMovie can't handle multiple video clips simultaneously: it simply lets you assemble clips only one-at-a-time, one after another.
But you can use an assortment of tools to prepare the different elements of your final movie, and then combine them one after the other with iMovie ..or with QuickTime Pro. Here's a simple movie which is just a collection of effects from Apple's 'Keynote' program ..which is intended to make slide projections for business presentations: it has plenty of effects in it, including '3D' and perspective transitions, and you can combine them to make a complete movie, like this, without ever using iMovie at all:
http://homepage.mac.com/francines/.Movies/SeattleVisits.html
So plan first exactly WHAT you want to show onscreen, then look for the individual
tools (..which may be several quite separate programs..) which will let you achieve each of those effects. iMovie may NOT be the best tool for the job, as it's just a "movie clip assembler".
However ..once you've built your individual, several component clips or sequences, iMovie can be used to 'weld' them all together. Here's an old movie from Apollo Reyes, made with a program called 'Still Life' (for zooming and rotating the separate pictures, and for turning them into movie sequences) and then using a very old version of iMovie to 'assemble' those separate sequences and dissolve each of them into the next, by using iMovie's built-in 'transitions' (..you may have to wait for 45 seconds or so for it to load):
http://homepage.mac.com/davidbabsky/iMovieTheater16.html
Envisage your movie in your head, decide what effects you need, then hunt for 'tools' which let you do each part of the job, then you can combine all the separate parts of your movie by joining them with iMovie, or QuickTime perhaps, or some other video 'editor'.
