awsome. now i get it!

Suggestion: explain the spawn a little more, because it's a misnomer to say it will spawn again (it shows up in your spawn box and you need to attack the board with it to get that unit back into play.

Ok, I noted where the units spawn, I should mention that they show up in your SPAWN territory, and Attack to the 2 locations on the board to the right and left of the ball.

Question - What happens to a player's units immediately after a goal? Particularly, what happens to the units that are on the ball and in the opponents goal?

They are removed from the board.  And since you have the ball to score, you don't spawn the turn you score.