Heres a guide to natures if you need reference or just dont know what they do:
att = attack
sp. att = special attack
def = defense
sp def = special defense
spd = speed
+ means stat goes up 10%
- means stat goes down 10%
x means normal stats
ADAMANT (att +) (sp. att -)
BASHFUL (x)
BOLD (def +) (att -)
BRAVE (att +) (spd -)
CALM (sp def +) (att -)
CAREFUL (sp def +) (sp att -)
DOCILE (x)
GENTLE (sp def +) (def -)
HARDY (x)
HASTY (spd +) (def -)
IMPISH (def +) (sp att -)
JOLLY (spd +) (sp att -)
LAX (def +) (sp def -)
LONLEY(att +) (def -)
MILD (sp att +) (def -)
MODEST(sp att +) (att -)
NAIVE (spd +) (sp def -)
NAUGHTY (att +) (sp def -)
QUIET (sp att +) (spd -)
QUIRKY (x)
RASH (sp att +) (sp def -)
RELAXED (def +) (spd -)
SASSY (sp def +) (spd -)
SERIOUS (x)
TIMID (spd +) (att -)
so natures raise one stat by 10% but lower another by 10%. 5 natures, the ones with Xs do not change stats at all.
The HP stat cannot be changed by natures
Hope that helps!