In your presentation, you have to distribute your stats.
Here is a list of the bonuses for each pair of stats:
Stats | Bonus |
0-1 | -5 |
2-3 | -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 |
20-21 | +5 |
22-23 | +6 |
24-25 | +7 |
26-27 | +8 |
28-29 | +9 |
At the creation of your Character, your stats can go up to 18.
You should keep your ability scores at least at 9 (but they can be lower if you want to be better at something else).