Psalm 2 continues where Psalm 1 left off. Psalm 1 introduces us to the single Man that blessing comes through; Psalm 2 shows us that He is the Royal Son of God Himself.
The nations rage and scheme and plot, but God does whatever He pleases (Psalm 115:3). The nations will submit to Christ, either willingly (and find blessing in doing so) or forcefully (and find themselves shattered like an iron rod smashing pottery).
Psalm 2 ends where Psalm 1 begins—with blessing or happiness. The blessed Man of Psalm 1 invites anyone and everyone to share in His blessing, if only they would take refuge in Him (2:12).
The only refuge from the crushing wrath of God is God Himself. Jesus takes the crushing on behalf of His people, and they are saved.
Notes from the study are available here.