Adam Clarke on Acts 13:4

Being sent forth by the Holy Ghost - By his influence, authority, and under his continual direction. Without the first, they were not qualified to go; without the second, they had no authority to go; and without the third, they could not know where to go.

Departed, unto Seleucia - This is generally understood to be Seleucia of Pieria, the first city on the coast of Syria, coming from Cilicia; near the place where the river Orontes pours itself into the sea.

They sailed to Cyprus - A well known island in the Mediterranean Sea. See on Act 4:36 (note).