Based on this chapter, what is the actual method or 'means' for achieving one's spiritual goal?

Chapter 45 presents a clear method for spiritual attainment, centered on the Guru and self-reliance. The process begins with developing dispassion (Vairagya) by renouncing the transient world. This is achieved by practicing discrimination, constantly reminding oneself that Brahman is eternal and the world is not. The chapter explicitly states that the Guru alone is the true Brahman. Therefore, the primary 'means' is to meditate only on the Guru. This constancy of feeling and focus is the path. This ultimately leads to what Chapter 45 calls 'undifferentiated worship' (Abheda-bhajan), where one sees divinity in all beings. This requires strong self-confidence and a renunciation of hope in others for spiritual aid.