स्पर्शान् कृत्वा बहिर्बाह्यांश्चक्षुश्चैवान्तरे भ्रुवोःप्राणापानौ समौ कृत्वा नासाभ्यन्तरचारिणौ
In plain words
Keeping external contacts outside, fixing the gaze between the brows, and making the inward and outward breaths moving in the nostrils even,
Word for word
Having made the external contacts outside, and the gaze just between the brows, having made the outgoing and incoming breaths moving within the nostrils even,
The commentators
Bhagavadgītābhāṣyam· avatāraṇikā
सम्यग्दर्शननिष्ठानां संन्यासिनां सद्यः मुक्तिः उक्ता । कर्मयोगश्च ईश्वरार्पितसर्वभावेन ईश्वरे ब्रह्मणि आधाय क्रियमाणः सत्त्वशुद्धिज्ञानप्राप्तिसर्वकर्मसंन्यासक्रमेण मोक्षाय इति भगवान् पदे पदे अब्रवीत् , वक्ष्यति च । अथ इदानीं ध्यानयोगं सम्यग्दर्शनस्य अन्तरङ्गं विस्तरेण वक्ष्यामि इति तस्य सूत्रस्थानीयान् श्लोकान् उपदिशति स्म —
In plain words
For renunciants who are steadfast in right vision, immediate liberation has already been declared. And the yoga of action, performed with one's whole being surrendered to the Lord, to Brahman, leads to liberation through this sequence: a purified inner being, then knowledge, then the renunciation of all action — Krishna has said this again and again, and will keep saying it. Now, having decided, 'I will teach in detail the yoga of meditation, the inner heart of right vision,' he goes on to teach the summary verses that carry it—
Close to the Sanskrit
For renunciants steadfast in right vision, immediate liberation has been stated. And the yoga of action, performed with one's whole being dedicated to the Lord, to Brahman, [as leading,] by the sequence of purified inner being, knowledge attained, and renunciation of all action, to liberation — this the Lord has said at every turn, and will state again. Now, at this point, resolving, 'I shall teach in detail the yoga of meditation, the intimate means of right vision,' he teaches its summary verses—