awesome

Cool, would work as a wilderness random encounter.

The negative in Intelligence and Charisma, presumably represents a lack of education and refined etiquette. 

Quote from Dr_Frederick >>

The negative in Intelligence and Charisma, presumably represents a lack of education and refined etiquette. 

 The intelligence is understandable. But the charisma penalty... I don’t know if that’s okay.

Why are tribal warriors less dextrous and not stronger than guards?

How do I add this to a campaign. I’m sorry if I’m being dumb but this is my first time. 

Depends on how you want them to interact with the setting. They'd probably be wary of outsiders, but they might kidnap children and make them members of their tribe to compensate for the harsh dangers of their lives.

You could have them live relatively peaceful lives, only bothered by outsiders hunting on their land, or they might raid merchant caravans. If they're struggling to find food or have a strong warrior culture, they might also raid small/weakly guarded settlements near them.

Depends on context. If the goal is to use them as a purely combat encounter maybe they're headhunters or under the thrall of some greater enemy and can't be saved until said monster is dealt with. For more nuance as characters, I recommend looking up real world stone age cultures from the past and present. They make great allies in truly remote areas since unlike orcs, goblins, or other monstrous races there isnt an inbred distrust or god instilled hatred of adventurers. One example I used them in was as the poorly trained shock troops of a despot, the party had previously managed to make a deal with their enslaved leader so when the party faced the big bads army a third turned on the rest before looting a town and running away. 

So silly they got rid of these from the new monster manual. 

Edit: Nevermind this was replaced with Warrior Infantry in 2024.