It would be easier if you just explained which stats are unclear to you.

Magical reinforce on weapons: the % is multiplied by your INT score, and the result added to your magical attack power when you equip the weapon.
Physical reinforce on weapons: the % is multiplied by your STR score, and the result added to your physical attack power when you equip the weapon.
Magical reinforce on armor: the % is multiplied by your INT score, and the result added to your magical defense when you equip the armor.
Physical reinforce on armor: the % is multiplied by your STR score, and the result added to your physical defense when you equip the armor.