Bhagavad Gita Chapter 6, Verse 12

तत्रैकाग्रं मनः कृत्वा यतचित्तेन्द्रियक्रियः | उपविश्यासने युञ्ज्याद्योगमात्मविशुद्धये ||

tatraikāgraṁ manaḥ kṛtvā yata-cittendriya-kriyaḥ upaviśyāsane yuñjyād yogam ātmaviśuddhaye

There, having made the mind one-pointed and controlling the functions of the mind and senses, seated on the seat, one should practice yoga for self-purification.

Krishna describes the meditation practice itself. 'Tatraikāgraṁ manaḥ kṛtvā'—there (tatra), having made (kṛtvā) the mind (manaḥ) one-pointed (ekāgram). This means: on the prepared seat, focus your mind to a single point—one-pointed concentration, not scattered attention. 'Yata-cittendriya-kriyaḥ'—controlling (yata) the functions (kriyaḥ) of the mind (citta) and senses (indriya). This means: you must control your thoughts and sense impressions—they shouldn't wander freely. 'Upaviśyāsane yuñjyāt yogam'—having sat down (upaviśya) on the seat (āsane), one should practice (yuñjyāt) yoga (yogam). This means: sit on the prepared seat and engage in meditation practice. 'Ātmaviśuddhaye'—for self-purification (ātmaviśuddhaye). This means: the purpose of meditation is to purify yourself—to clear the mind, remove impurities, achieve inner clarity. This is the core practice: one-pointed mind, controlled senses, seated meditation, for purification.