SV: छन्दसि उभयथा
AV: optional
Language meaning: at छन्दस् either way
Literal meaning: छ न द स य उ भ य थ अ
many (pull+roll = incoming tide rolling) verb(furrow/gather + connect) stand connect platform till
meaning explained: many incoming tides do furrow silted (steady connect) till platform
literal meaning of linguistic interpretation: छन्द् + असुन् many tides (pull+roll) + here furrow up pull + उभय + थाल् up steady/ground connect + platform till sand = many tides silt till platform.
Thuis instruction is not really about सार्वधातुक आरधधातुक aspects. Originally it was just warning that furrows will get silted.