Begin by conceptualizing what sort of character you would like to play. Is this character brawny, intellectual, or spiritual? Do they use firearms, fly drones, or eschew weaponry entirely?
Choosing a Race
Once you have a character concept, reflect on what sort of racial background makes sense for that character - not by which numbers look best.
Determining Attribute Scores
This method will generate one boon score, one flawed score, and three middling scores. First, roll 4d8 and reroll the lowest die. Next, roll 4d6 four times, recording the three highest of those sums, rerolling none. Finally, roll 4d4 and reroll the highest number. The five listed sums are your attribute scores, and may be distributed however the player wishes.
Select a Career Path
Look over your race and final attribute scores, and select which of the basic classes you feel most fits your character concept. The only prerequisite for selecting a profession or class is that the attribute requirement is met.