Verse 2.6.1.12

sa tata eva prāk stambayajurharati | stambayajurhutvāthetyevāgre parigṛhṇātyathetyatheti pūrveṇa parigraheṇa parigṛhya likhati harati yaddhāryam bhavati sa tathaivottareṇa parigraheṇa parigṛhṇātyuttareṇa parigraheṇa parigṛhya pratimṛjyāha prokṣaṇīrāsādayetyāsādayanti prokṣaṇīridhmam barhirupasādayanti srucaḥ sammārṣṭyājyenodaiti sa yajñopavītī bhūtvājyāni gṛhṇāti

Preview of English translation:

12. From thence he throws the grass-bush (stambayajus) eastwards. Having thrown away the grass-bush, he first encloses (the altar) thus (viz. on the west side), then thus (viz. on the north side), then thus (on the east side). Having enclosed it with the first line of enclosure, he (the Adhvaryu) draws (three) lines (across the altar) and [the Agnidhra] removes (from them the dust) which has to be removed. In the same way he encloses it with the second line of enclosure; and having enclosed it with the second line of enclosure, and smoothed it down, he says, “Place the sprinkling water on (the altar)!” They accordingly place the sprinkling water on (the altar); and the firewood and barhis they lay down beside it. He (the Agnidhra) wipes the spoons. He then walks up (to the altar) with the butter (and puts it down thereon, north of the sprinkling water). He (the Adhvaryu) takes butter, while 'sacrificially-invested.'

For a detailled translation, including proper diacritics and footnotes, go the full English translation.