Delayed sweep mode divides the screen into an upper and lower section. The lower section is a zoomed view of the full waveform above. The two horizontal knobs serve to adjust the zoomed region. The little knob moves the region left and right. Pressing the little knob moves back to being centered on the trigger. The big knob changes the size of the region.
A quicker and handier way to get to the same thing is to just press the big horizontal knob
The other menu selection is "Time Base". The usual thing is YT mode. To use XY mode, you need signals on two input channels. Roll mode bypasses the trigger and makes the scope work like a chart recorder.
Tom's electronics pages / tom@mmto.org