The model letters ف ع ل stand for the three root letters.
In the basic form ‘he did,’ the vowel on the middle root letter may be fatḥah, kasrah, or ḍammah. This gives the three patterns فَعَلَ، فَعِلَ، فَعُلَ.
The pattern helps us pronounce and remember the verb. It does not replace the verb's meaning, and it cannot safely be guessed from an English translation.