New version available here: vedabase.io

SB 3.28.8

śucau deśe pratiṣṭhāpya
 vijitāsana āsanam
tasmin svasti samāsīna
 ṛju-kāyaḥ samabhyaset
Synonyms: 
śucau deśe — in a sanctified place; pratiṣṭhāpya — after placing; vijita-āsanaḥ — controlling the sitting postures; āsanam — a seat; tasmin — in that place; svasti samāsīnaḥ — sitting in an easy posture; ṛju-kāyaḥ — keeping the body erect; samabhyaset — one should practice.
Translation: 
After controlling one’s mind and sitting postures, one should spread a seat in a secluded and sanctified place, sit there in an easy posture, keeping the body erect, and practice breath control.
Purport: 

Sitting in an easy posture is called svasti samāsīnaḥ. It is recommended in the yoga scripture that one should put the soles of the feet between the two thighs and ankles and sit straight; that posture will help one to concentrate his mind on the Supreme Personality of Godhead. This very process is also recommended in Bhagavad-gītā, Sixth Chapter. It is further suggested that one sit in a secluded, sanctified spot. The seat should consist of deerskin and kuśa grass, topped with cotton.