Happy to hear that you are enjoying the site. There are two ways to save videos:
1. Hover over videos on the BROWSE page and in the right corner of the thumbnail a little box with three lines and a plus line will show up. Click to add
2. When watching a video hover over the video and in the top right corner a text box saying 'Add to My List" will show up. Click to add
On a mobile device these 'add boxes' should be displayed without any hovering etc.
Hope this helps and thanks for watching!