The the How to play document says Weapon Attacks. If you’re attacking with a melee weapon, apply your Strength modifier to the damage, and if you’re attacking with a ranged weapon, apply ...
Let's say, we have there 1st level Monk, and he has STR 17/+3. Now we are calculating base attack with his Flurry of Blows. For first level, we have "Flurry of Blows Attack Bonus" -1/-1, plus 1st ...