First off, I would like to address Skimask and his comments. I am guessing from reading some of your posts that you are fairly intelligent when it comes to electronics and everyone on this forum is beneath you. Your sarcasm indicates that and I just want to remind you that this is a beginners forum, as someone else pointed out. My question is, why are you here. I can only think of two reasons. The first one is that you feel better about yourself by belittling the people on here that don't know as much about electronics as you do. The second one is that perhaps you are here to learn as well but good to throw a jab into those of us that don't know so much. I want to remind you what a forum is in case you weren't sure. It is a place where people of all ages and experience go to share information and knowledge, whether passing it along or absorbing it for their own consumption. It is a place to learn and when you open your mouth for no apparent reason, there is nothing to learn and nothing to share, so best left silent. If I am wrong about you I apologize but I have been a teacher for a long time and I recognize the tone. I feel sorry for sarcastic people. I used to be that person and it gets you nowhere. Enough said. If you can help, I would appreciate it and perhaps we can move past this. If not, have a nice day.
Yay!!! Grow a pair...either balls or ovaries, whatever the case may be. And fill out one of these:
http://www.funnyjunk.com/funny_pictures/1553678/The/I'm happy you've been a teacher.
Those who can, do. Those who can't, teach.
The wave rolls left or right because it's not being 'triggered'. It's being swept at various times...sometimes slightly faster than the input signal (rolls left), sometimes slightly slower than the input signal (rolls right). If the 'scope is 'triggering' on an input wave, it wouldn't start sweeping until the input signal went above or below a certain setpoint. But you'd know that if you really read and listened to some of those o'scope videos.
Is your probe connected to Ch1 or Ch2? Assuming Ch1, but the pictures shows a probe on both. Is it an X1 or X10 probe?
Set trigger coupling to AUTO, Ch1, center the trigger knob, holdoff knob to zero.
Channel 1, set to 1v/division, temporarily put coupling to GND and center the sweep (or move it a couple graticules down, whatever works), then put coupling back to DC. Make sure the VAR knob is pushed in or all the way towards CAL'D.
Also assuming the CAL signal is 1Khz. Set time/div to 10ms, Var Sweep to zero or CAL'D. When you see a bunch of waves, set it back to 1ms.
Slowly adjust the trigger towards + slope until you get a stable signal. There should be a fairly wide range of trigger setting to get a stable waveform on the screen.
If that doesn't work, try the other probe, the other channel, an external signal source. If none of that works, probably got a bad 'scope.