Phileas the Lumbridge Guide gives information to new players about where certain places are and what map icons mean. He tells other players not to tell people their password, and gives general advice such as what to kill, how to make money, and more. He does not specialise tutoring in any non-combat or combat skill.
He also plays a role in the Recipe for Disaster quest, where the player must save him from the Culinaromancer. To do this, they must visit Wizard Traiborn, and have him assist them in making a cake of guidance.
Lumbridge Guide is the solution to the hard anagram clue: BLUE GRIM GUIDED. He will give you a puzzle box.