Learning New Weapon Proficiencies

Occasionally, a character wants to use a weapon for which they are not proficient, or maybe learn how to use an exotic weapon for which no one has proficiency. In that case, learning a weapon is like learning a new secondary skill (tool proficiency). The character must find a trainer (or self-train) and spends downtime practicing with the weapon (the days do not have to be consecutive). At the end of that time (See Downtime - Training), the character is considered proficient in that weapon.
This does not give the character any proficiency in related weapons or weapon categories and cannot be used to “learn” armor proficiencies, only a single weapon can be learned at a time.