I read a series of books a few years back.
It was about a boy who, upon finishing school, decides to apply to an ad about a job. The ad states: Wizard's apprentice, no illusions. Real magic.
When he arrives for an interview, he reads a book about magic in the waiting room. He then walks through the door to the interview room, and this door is the portal to another world.
He starts to learn about magic from the book as he explores. He is soon attacked by wolves and saved by an archer. This archer takes him to a village that becomes his home.
In aiding the town he rids an old house (I believe) of some magical/ghostly shirt.
He gains skill fast, gains a home and enlists a younger boy who, due to a magical amulet, ages fast and becomes a skilled warrior.
In the end, he establishes a religion that the younger boy becomes the leader of at the end.