RTFM

Annie arrives at a house with multiple ground-level entrances. She rings one of the doorbells and waits. Nobody answers. She checks that it is the right door – yes, this is grandpa Karl's apartment. She rings again. Still nothing. She hears a window being opened and Isabelle quietly calling her from one of the adjacent houses:
Annie, we're over here.
She looks over, then walks up to the window.
Which door?
Number 15, I'll let you in.

Lucas and Karl are also inside.
Karl says: We needed a little more space. This place has been vacant forever, might as well use it.
Annie slides her shoes off and leans her bag against the wall. Then, they go into the living room where cables and computer parts are all over the floor. Lucas sits in front of the rack between two opened boxes. The rack's side panels had been removed, revealing the devices mounted inside and the cables connecting them. Lucas is pushing a circuit board into a half-assembled metal box that hangs out the front. Karl goes over to a stool next to the rack, cautiously avoiding stepping on things, and sits down.

Annie sits down on the floor next to Lucas and watches as he carefully inserts another board. Karl is reading from a binder of documentation and tells him to set some tiny switches on its front edge.
While grabbing the next board, Lucas says: Annie, can you take these and prepare the DIP switches?
He pushes the box over to her. It contains four circuit boards, all identical.
Uhm, okay. She takes one out and looks at it closely. It's full of electronic components on both sides and one of the edges holds a tiny red box with an even tinier row of switches on it.
Above is a meh description. Need naive description of DIP switches from someone who doesn't know.
So what do I set them to?
Karl tells her a combination and she tries to push the switches up or down as needed with her finger nails.
Lucas says Here, use this.
He hands her a ballpoint pen. Using it to flip the switches, she sets the combination Karl says, then hands the board over to Lucas and grabs the next one.

Karl takes the racks's power cable and plugs it in. Isabelle gets the terminal from a corner of the room and lifts it onto the rack. Meanwhile, Annie and Lucas start collecting the cables and loose parts from the floor. Isabelle plugs the terminal into power and Karl connects a cable between it and one of the devices in the front of the rack. They all gather around and Karl powers it on. He follows the same procedure that Annie and Isabelle performed in the library: Key switch at the top of the rack to RST, power up the hard drive, hold LOAD and key switch to RUN. Then, he pulls a floppy disk out of the documentation binder and inserts it into the computer. He enters some commands, the drive clicks a few times, and the terminal displays a menu.

[ SYSTEM DIAGNOSTICS v3.15 ]
----------------------------

1. Quick Test
2. Run All Tests
3. CPU Test
4. Memory Test
5. FPU Test
6. DMA Test
7. Serial Test
8. FDD Test
9. HDD Test
10. MTD Test
11. Load Module...

Choice: █

Lucas asks: Odds of this working first try?
Karl says: We will see...
He types a number and presses enter.

Choice: 2

Initializing...
Loading CPU Test...
  Registers:  Pass  Branching:  Pass
  ALU:        Pass  Long Words: Pass
  All Instrct:Pass  Stress Test:Pass
Result: PASSED
Loading Memory Test...
  Memory map:
    00000000-
Result: FAIL
Loading FPU Test...
  NC2K OpROM init
  FP Arithmetic Test
  SIMD Test
  
Result: FAIL