This link above has information on why your video isn't compressing the way you think it is because its a completely different function.
You're looking at a different kind of compressing which entails reducing the quality of the video in various kinds of ways for the best picture with the least amount of space. There are many tools to do that.
Xandrois9 is correct. You can record a video on your phone, copy that video to your computer and then compress it using Handbrake and put it on YouTube, that should be doable with what is posted above.