...then think of us as computer programs. If us computer programmers want a program to "know" something we can arrange for it to:

a) input the data by reading a file (analogous to a simulator putting something obvious in the environment for the simulatee to find),

b) put in the ability for the program to communicate with the user (simulator directly speaking to the simulatee),

c) include the "knowledge" within the body of the program itself (simulator creates a simulatee or modifies an existing simulatee to have the knowledge of the true state of the universe - if we are created, they can change the plans and modify us).