In order to display multiple tracks, the thumbnails do scale down. Click the + sign at the far left of a track, if not already in that mode, to expand the track vertically.
Between the video and audio tracks there's a line. Dragging it up or down may help, if a track has been partially hidden. Try switching to STORYBOOK mode temporarily.
Clicking on the transition X in a clip brings up the transition box. In its lower right-hand corner, set the length.