Brahman is real. World can exist as an appearance. An appearance of action can fully be combined with the reality of Brahman. Ultimately, internally one has to become monklike. When they become spiritual, they become less worldly. The more you go towards God, the more the world falls away from you. And how do you attain clarity? Shavana, manana, nidith, dihasana. If it helps, sit quietly with eyes closed in Vedantic meditation.
Swami Sarvapriyananda teaches the Mundaka Upanishad which one of the major Upanishads belonging to the Atharva Veda. Mundaka means ''shaved'' like a shaved head. The teachings revealed in this Upanishad are meant to leave the student clean, or shaved of the veil of ignorance. Indeed, the study of this Upanishad has been traditionally confined to the shaven-heads, or the sannyasins, who have renounced everything and devoted themselves exclusively to contemplation. The book consists of 64 Mantras (verses) split across Mundakas (parts) and Khandas (sections) as follows:
Mundaka 1 - Khanda 1 - 9 mantras (1.1.1 - 1.1.9)
Mundaka 1 - Khanda 2 - 13 mantras (1.2.1 - 1.2.13)
Mundaka 2 - Khanda 1 - 10 mantras (2.1.1 - 2.1.10)
Mundaka 2 - Khanda 2 - 11 mantras (2.2.1 - 2.2.11)
Mundaka 3 - Khanda 1 - 10 mantras (3.1.1 - 3.1.10)
Mundaka 3 - Khanda 2 - 11 mantras (3.2.1 - 3.2.11)
Reference books:
1. Mundaka Upanisad translated by Swami Gambhirananda - https://www.vedanta.com/store/mundaka-upanisad-with-the-commentary-of-sankaracarya_moreinfo.html (or)
2. Eight Upanisads Vol. 2 translated by Swami Gambhirananda - https://www.vedanta.com/store/Eight-Upanishads-Commentary-by-Shankara_moreinfo.html