i only know about pathfinder so i coul be wrong (though they are very similar)

you get a

1- base hp from ur race,

2- then add a base hp from class + constitution modifier

then repeat 2 for every extra level you get

so he should probably have more than 60 hp, as im pretty sure fighters get more than 10 hp per level (considering he has decent constitution)

You start with base HP at level 1. Every time you level up, you roll a die (which die is determined by what class you are playing) and add your constitution modifier.

Each class has what's called a Hit Die which determines how much HP a character accrues per level. At level 1, the character gets (typically) their full Hit Die plus their Constituion (Con) modifier ((##-10)/2, so 8 is -1, 14 is 2, etc). From there, Hit Die can be rolled as the character levels up or you can take the average for the HD, and add Con to that. So in this case, they're suggesting that Caesar, a 10th level Fighter (d10 hit die) would have on average 60HP total, though this would require them to have 'rolled' their level 1 HP pool (average of 5, plus a Con modifier of 1)

EDIT: that'll teach me to not refresh before finishing the post lol

You have 6 stats, Constitution is one of them. Your class dictates what size is die you use for HP on level up.

So a fighter uses a d10 so at level 1 he'd get the max of 10 plus constitution. Let's say 3 since he's thicc. So he starts with 13.

Then every time you level up you roll your hit die and add your constitution. So at level 2 the fighter rolls 1d10, let's say he rolled a 7. Then add constitution of 3 for a total of 10. So at level 2 the fighter will have 23 hp.