Rule 1: 1. The eight classes of the verb
A verb is named after the radical that gives trouble, using the letters of the model فَعَلَ: the first radical is its فَاء, the second its عَيْن, the third its لَام. So a verb with و as first radical is فِعْلٌ فَاؤُهُ وَاو, a verb whose fāʾ is wāw, and a verb with hamza as third radical is فِعْلٌ لَامُهُ مَهْمُوزَةٌ. The table below gives all eight classes with examples; the sentences here show a few of them at work.
دَرَسَ الْوَلَدُ وَفَتَحَ النَّافِذَةَ.
darasa l-waladu wa-fataḥa n-nāfidhata
The boy studied and opened the window.
Two sound verbs: every radical is a strong consonant.
مَدَّتْ أُخْتِي الْمَائِدَةَ وَعَدَّتِ الصُّحُونَ.
maddat ukhti l-māʾidata wa-ʿaddati ṣ-ṣuḥūna
My sister laid the table and counted the plates.
Doubled verbs: مَدَّ from م-د-د, عَدَّ from ع-د-د.
وَصَلَ الضُّيُوفُ وَوَجَدُوا الْبَابَ مَفْتُوحًا.
waṣala ḍ-ḍuyūfu wa-wajadu l-bāba maftūḥan
The guests arrived and found the door open.
First radical و: in the perfect they look sound.
قَالَ أَبِي: نَامَ الصَّغِيرُ.
qāla abī: nāma ṣ-ṣaghīru
My father said: the little one has slept.
Second radical و or ي appears as a long ā in the perfect.
سَأَلَ الضَّيْفُ عَنِ الطَّرِيقِ ثُمَّ بَدَأَ يَمْشِي.
saʾala ḍ-ḍayfu ʿani ṭ-ṭarīqi thumma badaʾa yamshī
The guest asked about the way, then began to walk.
سَأَلَ has hamza as second radical, بَدَأَ as third; يَمْشِي has ي as third.