If I were to watch a video on how to do something on youtube, is it legal to post that same method in my own video? Say, for example, I saw a minecraft video on how to create something. Would I be able to make my own video creating the same thing in the same way without citing the source? What are the bounds?
An "idea" is not copyrightable, though the video itself is.
There's nothing legally stopping you seeing a video about a villager apartment, for example, and making your own "How to make a villager apartment block" video. That said, some people will consider it unethical- provoke Youtube drama at your own risk.
However, there are some things you can't steal. The script, for example, can be covered by copyright. If you were to repeat the wording of large sections of the video, that would not be allowed. Similarly, including clips of the video itself would be problematic.