Here are the key components of a table tennis game to look for if you want to learn from observing.
Watch how he goes through his pre-point routine before stepping up to the ping-pong table.
2. Serve and receive
Watch how he stands to receive a serve – his distance from the table, his racket position, his racket height, his foot positioning, his balance. Watch when he serves – his positioning, his backswing, his contact point, his follow through, and his return-to-the-ready position.
Watch how he moves for each ball, watch how he anticipates for the next ball, watch how he continues to adjust and re-adjust for each ball with large leaps as well as micro steps.
4. Shot Selection
Watch how he chooses when to loop, when to block, when to counter-loop, when to stay close, when to back up – watch his shot selection.
5. Time Between Points
Watch how he takes his time between points. Watch as he walks back to pick up the ball, how his body language is showing his thoughtfulness as he mentally gears up for the next point.
Instead of trying to watch all of these elements at once, I would recommend watching a short YouTube video five times. Each time, watch a different aspect of the table tennis game as outlined above. By training yourself to watch each aspect separately, you will better be able to learn the details of the sport of the table tennis.