That's a nice scope!
There are at least two ways to learn how to use one: a) Screw around with it 'til you figger it out or b) Read a manual and/or follow step-by-step instructions. Frankly, I think method a) is by far the best way to start out as you learn a more general methodology by accident.
Some tips:
1) Look for youtube instructions like
https://www.youtube.com/watch?v=h8MamgRaLsM
2) Do you have a probe? If not, get a couple of 60MHz or higher 10x probes from MPJA.
3) Set the timebase for .5ms./cm. this is a good place to start for looking at the servo pulse coming out of your receiver. Your probe should have an alligator clip for ground that you need to connect to the black servo wire.
4) Set the vertical mode to channel 1 and channel 1 Volts/Div to 1V/cm. Note the brackets on the scale for 1x and 10x probes.
5)Set Horizontal mode to "A". Set A trigger source to channel 1. Set A trigger to rising slope (Button out). The level knob is something you'll need to adjust to get your pulse to lock on. Set your trigger to Auto; The Norm option will not give you a trace unless the trigger level knob happens to be in the right place.
6) Connect your probe to a servo pigtail to get the signal out of your Rx
Have fun! There are Kraft manuals on the internet that have a lot of theory and scope trace information you can learn from.
-Ron