Gaining a Sidekick:
Sidekicks can be a friend, an animal companion or even summoned via spells. You can probably even hire some in larger settlements. You are limited to a number of Sidekicks equal to your CHA modifier.
Creation:
All sidekicks start with the same standard array for their stats: 14, 13, 12, 10, 10, 8 which can be placed in any order.
Next, you will pick one of the following roles for them; Caster, Scrapper, Brawler, Animal Companion or Familiar. This role will determine their Hit Die Type, starting equipment, access to skills & abilities as well as when they will gain new abilities and proficiency bonus increases.
Once the role has been picked, their starting hit points for level one is equal to the max on their die type + constitution modifier + any skill bonuses. After level 1, they will roll their HD as normal. Sidekicks will gain proficiency in one saving throw, chosen from the list in their role.
Death:
If a sidekick ever reaches zero hit points during a fight, they do not immediately die. Instead they are in a “downed” state just like a PC would be. However, they will die if they fail a death saving throw before being stabilized.
Caster:
Hit Dice: 1d6 + CON modifier (6+mod at lvl 1)
Saving Throw: Pick One - Charisma, Intelligence or Wisdom
Skills: Choose one from Arcana, History, Insight, Investigation, Medicine or Religion
Spell List: Choose one from Cleric, Druid, Sorcerer, Warlock, Wizard
Scrapper:
Hit Dice: 1d8 + CON modifier (8+mod at lvl 1)
Saving Throw: Pick One - Dexterity, Charisma or Intelligence
Skills: Choose three from Acrobatics, Athletics, Deception, History, Insight, Intimidation, Investigation, Perception, Performance, Persuasion, Sleight of Hand, Stealth
Brawler:
Hit Dice: 1d10 + CON modifier (10+mod at lvl 1)
Saving Throw: Pick One - Strength, Constitution, Wisdom
Skills: Choose two from
Animal Companion:
Hit Dice: 1d8 + CON modifier (8+mod at lvl 1)
Saving Throw: Pick One - Strength, Dexterity or Constitution
Skills: Choose One - Perception, Intimidation, Stealth
Familiars:
Hit Dice: 1d4 + CON modifier (4+mod at lvl 1)
(additional info in Sidekick doc)