Bill's Town - The Woods
Artifact #18: Pills Note
Next to the gate you boost Ellie over is a red brick building. Enter it and head upstairs to find a small office. On the other side of the desk, you'll find this on the floor.
Artifact #19: Note to Bob
As you head down the street past the evacuation notices, make your way to the barricade at the end. Tangled in the barbed wire is another artifact.
Firefly Pendant #8
On the same street is an RV. Climb to its roof to find a pendant up here.
Artifact #20: Perimeter Note
Near where you encounter Bill's wire traps is the Marquis Music Store. Enter and head to the back room to find this atop a desk.
Artifact #21: Note to Rachel
When you return to street level, make a left and follow the alleyway to find a shaking door. Enter this house and head upstairs to the living room. After taking out the infected, you can grab this off of the table against the wall.
Bill's Town - Safehouse
Artifact #22: Bill's Map
Once inside Bill's safehouse, look to the stack of crates near the bar. This rests atop them.
Artifact #23: Fences Note
Then turn around and enter the small back room to find this next artifact atop a small table.
Training Manual #1: Shiv Sharpening
Before leaving the first floor, check the bar to find your first manual.
Artifact #24: Hunters Note
Make a right at the top of the stairs to enter a kitchen. You'll find this on a small table inside.
Firefly Pendant #9
As soon as you exit the safehouse, make a right and head to the end of the street. Look up to spot a pendant dangling from a streetlight. Shoot it down to put it into grabbing range.
Artifact #25: Bombs Note
When heading through the top floor of the church, take right before the exit window to enter Bills' room. On his desk is another artifact.
Bill's Town - Graveyard
Firefly Pendant #10
After sneaking through the church garden, you'll move through some backyards. Make your way up the hill to the large green house and enter. Locate the laundry room, and you'll spot this pendant atop the washing machine.
Artifact #26: Boy's Diary
When exploring the last house before the high school, head upstairs and take a right. Make another right inside this children's room to find an artifact near the window.
Bill's Town - High School Escape
Artifact #27: Note from Frank
Before pushing the car, take some time to explore the house. Head to the back room to find this atop a desk.
Artifact #28: Note from Frank (Crumpled)
After collecting the Note from Frank, speak to Bill in the garage. He'll read the note and throw it on the ground in anger. You can then pick the note up again - it counts as another collectible.