In plain words
The poet, of the Lord: His standing on the matchless mountain [Tirumalai], his sitting in heaven [Paramapadam] and his lying in the good [milky] sea of great waves were all in the days when I was as nothing, not knowing the way. Now the Wondrous One, who lies on Ananta, the First Cause, Mādhava [Lord of Śrī]: his standing, his sitting and his lying are in my heart.