If you're really trying to learn, start simple. That 5th seal vlog you posted, that's a pretty simple chopped beat. By simple I just mean the song you're sampling generally stays in 4/4 time. Sampling stuff out of 4/4 is going to make it harder (especially if it has a real drum presence to it), but basically with 4/4, when just starting out sampling, you can pretty easily chop on each beat in the song. Meaning, you can either chop a measure into 2, 4, 8 etc. parts (generally no more than that).
From there you can try and switch it up and experiment with different chop points. Good luck!