I don't follow, but if you create that compares points = 300 it will automatically trigger when points = 300.
The game runs down the event sheet top to bottom every tick so it repeats the code continuously and triggers that code when it is true/applys to situation.
If variable points = 300
then do this
set points to 0 (so it can count back up to 300)
will trigger everytime points = 300.