After you have acquired the snake key from the corpse in the demolition room you can start search for the red and blue access keycard cards in Resident Evil 7.
Blue access card - Location
First got to the first floor of the main house and open the children's room opposite the recreation room with the snake key. Here you can find a trophy with a lampshade. Look at it in the detailed view and you will discover a red button, which, after triggered, will drop the ladder in the room leading to the attic.
When you get to the top, you come back to another puzzle. Position the metal piece accordingly on the base and forms the shadow of a man with ax. Thereupon the model house opens to the right of it and unlocks the blue access card.
Red access card - Location
Now go to the parents' bedroom on the first floor and close the door. Right in front of you see a bed and under it there is a light shines from the corridor. Then look at the globe on the left side of the table and read the message. The message refers to the clock on the table, the time of which you have to adjust in order to trigger a Bed mechanism and then leave the passage.
There is no other clock in the room itself, but when you go out again, you can see a wall clock showing the time "10:15" on the opposite side. Set this time also in the bedroom in the clock to unlock the secret. Follow the path and get to the workshop in the processing area. Here you can take the red access keycard from the table. You must then again go through the processing area, since the way back to the bedroom is blocked.
Now you can open the door with the keycards and face the riddles of Lucas Baker.