In The Casting of Frank Stone, you'll need to fix several generators at some points to progress - much like in Dead by Daylight itself. In fact, throughout the game you'll need to complete three different generators. Here's how to repair the first generator in the game, including where to find the generator parts and how to use them on the machinery.
How To Fix The First Generator
To fix the generator, you'll need to find the two parts for it. Thankfully, they're both nearby in the area - but you'll have to do some looking around to find them, since they're pretty carefully hidden on the tables and this area is fairly large.
Where To Find The First Part
The first generator part looks like a big screw. You can find it on a table near the generator, under a sign that says "Danger: Keep hands out of machinery." Just pick up the item to add it to your inventory.
Where To Find The Second Part
The second generator part is found on other table further back in the area. Head back the way you came from and check out the tables near where Chris is standing waiting for you. On one of the tables, you'll see a large generator part next to a topped stool sitting on its surface.
Once you have both items, make your way back to the generator and interact with it. You'll see a prompt that says Repair. As you repair the generator, you'll have to hit skill checks - just like in Dead by Daylight. Hitting skill checks allows you to progress on the generator, while missing them will cause you to lose progress. You'll need to complete this process for each of the two parts.
Now that you've repaired the generator, you're done with this area and can progress through the door that opens with a button press. While it was previously locked to you, the generator being powered gives you access.