The easy way to make slide shows is to use Automate to Timeline from a set of stills in the project window. You can set up a default transition and timings. You can also lay down a music track on the timeline, tap the number pad asterisk key on the beat to create a series of timeline markers, and then automate to change pictures on te beat.
There isn't an automatic way to get random transitions, though.
On-line help gives more detail if you need it.