Abihdhamma is object of vipassanā. So if you want to understand abhidhamma, you must connect it to vipassana-object such as paṭiccasamuppāda (causes and effects).
Kamma is saṇkāra-paticcasamuppāda. Effect of kamma is (paṭisandhi) viññāṇa=born=Resultants Citta&Cetasika&Rūpa.
If you born in rūpabhramma-bhava, you are never taking any disagreeable object. But If you born in niraya, you are never taking any agreeable object. Kamma make destiny of born. Born make destiny of resultants-nāmarupa, resultants-6 āyatana, resultants-phassa, resultants-vedanā.
Born is a big chance. I was born in a buddhist country, so it is so easy for me to know about buddha's teaching.
My english is terrible.