This page of The Last of Us game guide contains information on where to find the training manuals and tools in the Pittsburg chapter. Those items are collectibles-secrets. Our walkthrough indicates the exact location of each artifact and pendant.
The set of tools is in the bandits' garage. You will get there right after the first fight.
Health Splinting 1
Description: Increases the effectiveness of healing in the battlefield.
You can find it on the first floor of the bandits' garage (in the room with the mattresses). It is on the shelf to the left.
Shiv reinforcement 2
When you manage to climb the ladder to reach the next floor of the lobby, turn right and slip past the hole carefully.
You will find there a suitcase on the floor with a safe combination in it. .
You need to return downstairs to find the safe in the room with the counter. Open the safe and collect the manual.
Melee Knots 1
description: Increases the durability of sharp tools
After you are saved by Ellie, climb up and go left.
This way, you will reach a broken staircase.
Below, go ahead until you go past two destroyed elevators. Right after that, you will notice two red chairs and a desk with the manual on.
Molotov Construction 1
Description: Increases the radius of the incendiary bomb.
After you talk to the two black brothers, explore the flat that you are in. On the table top, in the kitchen there is the manual.