When Dakmor Salvage enters, Thranduil the Strategist and Kodama trigger.
Resolve the Kodama trigger, choosing to put nothing onto the battlefield.
Holding priority, activate Troubled Healer by sacrificing Dakmor Salvage.
The Gitrog Monster's second ability triggers, causing you to mill two cards and return Dakmor Salvage from your graveyard to your hand.
If a land was milled this way, The Gitrog Monster's second ability triggers, causing you to draw a card.
Resolve the Troubled Healer ability
Resolve the Thranduil the Strategist trigger, creating a token.
When the token enters the battlefield, Kodama triggers, putting Dakmor Salvage from your hand onto the battlefield.
When Dakmor Salvage enters the battlefield, Thranduil the Strategist triggers.
Repeat from step 4.
Proceed to your cleanup step, and discard Dakmor Salvage and any other card(s) as needed down to your maximum hand size.
The Gitrog Monster triggers, causing you to mill two cards and return Dakmor Salvage from your graveyard to your hand.
Repeat, as you will still be over your maximum hand size and will be required to discard again.
This intricate loop transforms a simple land drop into an endless cascade of triggers by leveraging the replacement effect of dredge. Whenever you sacrifice Dakmor Salvage to Troubled Healer, The Gitrog Monster prompts you to draw a card, which you replace with Dakmor Salvage's dredge ability to feed it back into your hand and mill your library. Meanwhile, Thranduil the Strategist rewards each returning land with a fresh token, whose entry triggers Kodama of the East Tree to instantly drop Dakmor Salvage right back onto the battlefield.