What did Nehemiah do when he heard about the condition of Jerusalem?

He sat down and wept, and for days he continued grieving and fasting and praying [1:4]

What did Nehemiah confess while praying before the God of heaven?

He said that Yahweh is the God of heaven who keeps his covenant, and that the people of Israel, himself, and his father's house had sinned [1:4; 1:7]

What did Nehemiah request while praying before the God of heaven?

He requested that Yahweh would listen to his prayer; that Yahweh would call to mind the word he commanded Moses, promising to gather the scattered Israelites if they returned to him and followed and did his commandments, and that Yahweh would give success and grant mercy to him [1:4; 1:8-11]