In every sensory experience, awareness is there. Buds will say no, but that awareness comes and goes with the sensory experience. Without it, you would not experience any of it. So in all these things, learn to recognize that the one common unchanging awareness. Presence and absence are both noticed by the same evadne internally. Thoughts, feelings, emotions, ideas, desires, happiness, misery, they're all different from each other,. But a barness is common to all of it.
Swami Sarvapriyananda teaches the Katha Upanishad, one of India's most revered texts which is also a part of the Vedas. It is a collection of philosophical poems representing a conversation between the sage Naciketas and Yama (god of death). They discuss the nature of Atman, Brahman and Moksha(liberation).