The Buddha said, “If you are attached to the outer forms, then you will not see Tathagata (Buddha).” So, do not be attached to anything from the outer forms; just sit and meditate in an empty room. Do not be attached to outside shape or forms, then the inner (Heavenly) Light will manifest. Do not be attached to anything, do not think of anything, then the miraculous (inner Heavenly) Light will appear. That is a Buddha mind. That’s why it is said in the Diamond Sutra, “One should develop a mind which does not abide in anything.”
Regarding the realms, do not be attached to any realms. Maybe today you see this realm, tomorrow, you see another realm. Or next month, you see another realm, and one or two weeks later, you see another one. Do not be attached to anything, continue to practice spiritually. Whatever realm you saw, that is just temporary, to let you go to another level.