A creature has six ability scores (Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma), each of which has a corresponding modifier. Add the modifier when you make a D20 Test with the corresponding ability or when a rule asks you to do so.
Determine your ability modifiers using the Ability Scores and Modifiers table. Write the modifier next to each of your scores.
Score
Modifier
3
−4
4–5
−3
6–7
−2
8–9
−1
10–11
+0
12–13
+1
14–15
+2
16–17
+3
18–19
+4
20
+5
Determine your ability scores by using one of the following three methods. Your GM might prefer you to use a particular one.
Standard Array. Use the following six scores for your abilities: 15, 14, 13, 12, 10, 8.
Random Generation. Roll four d6s and record the total of the highest three dice. Do this five more times, so you have six numbers.
Point Cost. You have 27 points to spend on your ability scores. The cost of each score is shown on the Ability Score Point Costs table. For example, a score of 14 costs 7 of your 27 points.
RollQuest ships the D&D 2024 SRD as a content pack, on a 5e character sheet that does the maths - roll from the sheet and let the numbers work themselves out. Free to start.