Tip: Hit Pause by clicking on the Video and allow Video to Buffer for a few, before watching video; it will work smoother.
There are many controls to use in the Player; not all player skins are the same; so I will only show icons from the default player.
The Full Screen Button (I recommend you watch video's full screen; hit Esc to to go back to normal)
The Play Button ; you can also click anywhere in the video to pause or play
The Pause Button ; you can also click anywhere in the video to pause or play
The Progress-bar ; it shows where you are, how many minutes have played and how many minutes total.
The Stop Button
The Volume control
Note: if you change the Player skin in the middle of a video it will restart it from the beginning.
You can Right click on top of the video and pull up a menu.