The scene is recorded on the film as a negative image. In other words, whites are black, blacks are white, etc. That means then, that the white parts of the negative image are actually unexposed silver particles and the black parts are fully exposed. Film, unless packaged in a light-tight container, must be handled in total darkness both when loading the camera and processing. For this reason, it is easier to use photographic paper, which can be used under low level photo lights, in the pinhole camera.
Photo paper is also a lot less light sensitive and therefore less likely to react to stray light.
Later, you can choose to experiment with real film as your experience increases. Photo paper can be purchased in a wide variety of sizes with the most common being 5 x 7 and 8 x 10. The paper will probably need to be cut to fit the inside of your pinhole camera. The cutting and loading will have to be done under safelight , a dark red, or yellow photo light. Before you turn on the fight and leave the darkroom you will need to place your finger gently over the pinhole to prevent stray light from exposing the film.