Thanks for helping @EmilyJane !
I've now read through my whole manual, although it feels like I am going to have to read through it several more times 
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I tried touching the probe like @Grumpy_Mike suggested, and its a v shaped wave at 60 hz, with peak to peak reaching ~10 volts!
You're welcome. You'll be an expert in no time!
I went back and read my manual and my scope operates the same as yours. Probably made in the same factory, lol. The "zoom" mode basically serves the same purpose as a variable sweep setting and you can select whatever part of the waveform you want to magnify.
How exactly do you make a TDR? I know you need a signal generator and an oscilloscope (and a cable to test of course), but how do you actually make it?
This looks like a fun project. I just ordered a couple of the BNC adapters I don't have. I think i'l try it first with my Siglent function generator and then the Schmidt trigger if the rise time is too long.
Thanks @LarryD !
My o'scope has a 1khz square wave for calibration and such builtin. Could I use this as the "signal generator" circuit in that video? If so, how?
Oh, beneath the channel ports, it says "All inputs: 1MΩ / 18pf".
You need a square wave source with a very low rise time (<5ns) so that the rising edge of the source does not overlap and obscure the rising edge of the reflection. The rise time determines the shortest distance you can measure in a cable.
Look at around 6:15 in the video.
As the video states you need a fast rise time signal ( about 2ns).
The calibration port on scopes have slow rise times.
You could feed the calibration signal into a Schmitt trigger input gate, however, you might as well copy the circuit the speaker talks about in the video.
The same guy has this:
Thanks @LarryD and @EmilyJane !
Yeah, I just checked the rise time on my o'scope generator; its over 47us!!!!
So, I tried the last video that you posted @LarryD , but maybe im doing something wrong? It doesnt seem to be working.
This is what my o'scope displays (I used the print function @EmilyJane 
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I have my probe attached to a 47Ω resistor and the end of a spool of wire. The GND clip from the probe is clipped to the negative terminal of a new 9v battery. I then tap the end of the resistor on the positive terminal of the battery just like in the video, and the o'scope displays the picture above.
Possible reasons:
I dont know what im doing exactly on the o'scope (although I think I set everything correctly)
I used a 47Ω resistor as I do not have a 50Ω
the wire is 20awg on a spool instead of a straightened coax cable
Im using the probe that came with the o'scope instead of a direct bnc connection
This needs to be 2 strands, i.e. not a single strand of wire on a spool.
example:
twisted pair Cat6.
Oh. How did he test a single strand coax cable? My spool is actually 4 strands; is that fine? I am only connecting everything to one of the strands, and the other end is open.
How did he test a single strand coax cable?
Coax has a center conductor and the shield.
My spool is actually 4 strands; is that fine?
Fine, use 2 of these wires, usually two that are paired.
Ah, I figured that was how; just wanted to make sure.
Im not sure if any of the 4 strands are "paired"; it is a really old spool and 2 of the strands are white, while the other 2 are black. I use my multimeter to tell which goes to which lol.
So, one strand goes to the o'scope, and a second strand goes to gnd?
Edit:
Also, my 4 strand wire has a ground shield (looks like aluminum foil), and a ground wire too.
Thanks @LarryD for taking the time to do a test!
So, I tried attaching the ground wire in my cable to the end terminal of the 9v battery, in addition to what I already have. After zooming out quite a bit, I get this:
Is that what it should look like? Based off of that, this spool is 392 feet (I'm not sure how long it is besides that; no info on the spool at all).
Edit:
Measurement:
Might be reasonable.
Yay! Would this work for a wireless dog fence wire? It’s single strand solid copper wire; no gnd or gnd shield.
You need paired wire (2 wires) for this to work.
Ah, shucks. My dog fence is always cut 
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Thanks for your help @LarryD !
Successful measurement of an extension cord:
That makes it out to be 23.5 (24) feet long 
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See this post for a number of links to scope videos.
