# the king of Assyria mobilized his great army, sending Tartan and Rabsaris and the chief commander

Sennacherib sent a group of men from his army to Jerusalem to meet with King Hezekiah, including Tartan and Rabsaris.

# Tartan ... Rabsaris

"the Tartan ... the Rabsaris" or "the leader of the soldier ... a court official"

# the conduit of the upper pool

the channel where the water stored in the "upper pool" flows into the city of Jerusalem

# stood by it

"and waited there for King Hezekiah to meet with them"