On the right-side top corner, you will find two icons of camera and bell. If you click on camera icon you can upload the video. You will get a new page as shown below, click on the arrow icon to select the video files to upload. Select the required video file to upload from your computer.
After uploading video, you have to write Title, Description, Tags and other sections of the YouTube video. 15 minutes is the default max length, but that can be extended by visiting https://www.youtube.com/verify The webpage says to make sure you’re using an ‘up-to-date’ version of your browser to upload files over 20GB. The current (as of Nov 12, 2016) maximum file size is 128GB and the maximum duration is 12 hours. (As per the Stackoverflow).
After the video is uploaded, we need to fill the details of Title, Description etc. This will help the video to get found on Google and other search engines.