iMovie. clip bin or library

On my newish iPad, I am having fun with iMovie. But my selection of clips and other media do not show up in any kind of storage space—a bin, a library, a list…whatever. Just wondering why? On various tutorials, the programs all show a “bin” sort of area appearing automatically in the workspace. That would be very handy for previewing, rough editing, etc. Why am I not getting this? Should I be on a larger MAC interface? Or is there a paid version of this app that I need to buy? Also, my iPad workspace seems to be missing a few sliders and “buttons” referenced routinely and casually in various tutorials. I am a very experienced user of MACs for music, photography and more…