Character Creation Basics

In order, it probably makes sense to select a class first, then a race, and then a background, but, obviously, this can be done in any order you want.
Once you've selected the basic aspects of your character, the next step is determining their ability scores and skills. In determining your character's ability scores, each of the seven start at a value of 5, which has a modifier of 0; any point above 5 will raise the modifier by +1, and any point below 5 will have a modifier of −1. Your character also receives a racial bonus of +1 to one ability score. The ability score that receives this bonus is determined by the race, but usually multiple options are presented. You then have seven points to distribute amongst your character's ability scores. You may lower ability scores below 5, gaining a point to allocate for every point you remove from a score. This will mean your character will have a net modifier of +8 in total. You can allocate an ability score as low as 3 and as high as 7, with the exception of an ability score that receives a racial adjustment. Ability scores that receive a racial bonus may be lowered to 4 and raised to 8.
After finalising your character's ability scores, then select the skills they are proficient in. Your character will receive some skill proficiencies or proficiency choices from their race, background, and/or class. If a class feature lets you pick two proficiencies from a list of five skills, then you must choose two of those five skills that you want your character to be proficient in. If multiple sources give you the same proficiency choice, you may not select it twice; if multiple sources give you the same proficiency, you do not gain any extra benefit.
If you have not yet already, you should now select your first class perk. The list of perks available to your class can be found on the page for your class.
Finally, you must choose your character's starting equipment. The starting equipment options may be found on the page for your class; they usually include one or more weapons, a set of armour, and a pack full of other equipment.