You can find some information from google >>> mononofu wiki
And here is you answer
Attack (ATK) increases damage dealt (before damage modifiers).
Light Cavalry Attack +5% only works if your class is on the left side of the cavalry tree.
Damage (DMG) changes the final damage after attack/defense is calculated.
Defense (DEF) reduces the damage your troops take.
Reflect does not decrease the damage you take, only deals damage to the enemy based on the damage you take.
Power (POW) increases your damage dealt.
Leadership (LED) reduces your damage taken.
Intelligence (INT) can improve some skills of your Generals.
Speed (SPD) decides who strikes first.
Good luck, have fun!