A character is six decisions and a name. This section walks them in the order that costs you the least backtracking — class first, because it decides the most, and the numbers after the things that change them.
If you are new to the game entirely, read Playing the Game first — it covers how a session works, which is most of what makes these choices mean anything.
Terms with a dashed underline open their full definition from the Rules Glossary; anything the database holds in full — classes, species, backgrounds, feats — is linked rather than repeated here.
The character builder walks these same six steps as a form, if you would rather fill one in than read.