Go to Youtube, find the suitable video to your hub. There is a tab named "Embed". Click it, if the owner of the video allow to embed his or her videos, you can get the embed code by click on this. If the owner allow embed video means he or her already given permission to use the video. So, no need to get any permission.
Then go to your hub. Go to edit, add a video capsule. Enter the code which you took from youtube. Save the video capsule. Thisi is very simple way of doing this. I hope it would help you to solve the issue. If you need any further help pls let me know. Im happy to help you.