A young man dressed up with a yellow tie jumps against a wall and one foot is left against the wall to push away.
The young man is jumping against a wall.
There is no difference between 'a young man' and 'the young man'; 'Is jumping' is synonymous with 'jumps'.
There is both a young man jumping against a wall.
The young man is jumping against a wall with a yellow tie and one foot is left against the wall to push away.