The people you meet are unlikely to look, act, or sound like eternal spiritual beings. Moreover, nearly all would probably deny being one if you happened to ask them about it, but that is irrelevant. Just focus on yourself as an eternal spiritual being interacting with other eternal spiritual beings.
You don't have to do anything special during this "experiment" other than remain conscious of the fact that you are regarding yourself and the people around you as eternal spiritual beings.
Once you have "mastered" that, extend the awareness to everything else you encounter or see -- plants, trees, clouds, animals, landscapes . . . all of it. Treat everything as eternal beings or parts of eternal beings interacting dynamically within Creation.
Keep track of how long you can "keep this up" and then reflect upon the experience after your consciousness drifts or falters out of the experiment and settles back into "the real world".