You train your minions in how to make themselves useful.

Your minions get a +1 bonus to all tests of skill that you have taken a course in or have at least one interest point in.

Your minions (buddies, familiars, and pets) can assist you on tests of a skill that you have taken a course in or have at least one interest point in, where it is reasonable for them to do so due to this training.
(Without this ability, minions can only provide meaningful assistance on certain tests of skill, such as tests of Strength, Seeking, or providing a distraction for Roguery. This ability expands the tasks they can assist with including allowing them to help fetch the right tools from among a collection for artifice, help craft poisons or alchemicals, help craft healing items or treat injuries, or help alter a spell using spellcraft.
They generally still cannot assist on tests of knowledge, such as identifying a spell with spellcraft, or knowing something due to intrigue or monster lore.
A pet or summoned creature may help identify whether something is poison or not with Poisons or Survival, but may not know the particulars.).

Additionally, when you pass an extended test of skill that one of your minions successfully assisted you on, you get extra effort.
(Having more minions assist you does not increase this bonus.)