To generate your ability scores, you will use point buy. Every stat starts at 10, and you have a pool of 15 points to add to these scores. You may subtract from the starting 10 scores to add a point to your pool, but a score cannot go below 5, and a score cannot exceed 20.
Once you have chosen your stat array, you may assign the six numbers to your different ability scores: strength, dexterity, constitution, intelligence, wisdom, and charisma. If you wanted your character to be strong, you would assign a high number from your stat array to your strength score
You may not have an ability score that is over a total of 20 during character creation, even with adding racial bonuses and/or feats. If you add all of your ability scores up after you finish this step, you should get a total of 75.
After you have generated your stat array as described above, and have assigned them all to an ability, you may increase one ability by +2, and a different ability by +1. You cannot make an ability score exceed 20 this way. If you add all of your ability scores up after you finish with this step, you should have a total of 78.
Every character gets to pick one feat, as detailed later, upon character creation. If the feat gives an ability score increase, this free feat cannot make a score exceed 20.
When you are allowed to increase your ability scores, typically when you level up at levels 4, 8, 12, 16, and 19, and you have an ability score at 20, it takes two points to increase your ability score by 1. For example, if your strength score is 20, and you wanted to use the ability score improvement feature to increase your strength even higher, you would have to use both the additional points to increase it to 21. If you chose a feat instead, and it gives you only a +1 to an ability score, you cannot save it for later. You need to get +2 from a single source to increase an ability score by 1 when you are at or passed an ability score of 20.
As your character goes on adventures and overcomes challenges, the DM might tell the players that they have gained a level. When your character gains a level, his or her class often grants additional features, as detailed in the class description. Every character’s proficiency bonus increases at certain levels, as shown in the Proficiency Bonus Chart below. Each time you gain a level, you gain 1 additional Hit Die. Roll that Hit Die, add your Constitution modifier to the roll, and add the total to your hit point maximum. Alternatively, you can use the fixed value shown in your class entry, which is the average result of the die roll (rounded up). When your Constitution modifier increases by 1, your hit point maximum increases by 1 for each level you have attained.
The ability modifier that corresponds to each ability score is listed below. If you somehow acquire an ability score that is not listed on the chart, the formula to find the modifier is your Ability Score minus 10, then divide by 2, rounded down.