What to do first
Crack baluts to find ducks, bring the ducks back to your base and use the cash they generate to upgrade tools and speed. Plan how you will return before trying to take a rarer duck past the guards.
Where to check codes
The Roblox listing has a developer-maintained Codes section. Use the latest spelling listed there and the in-game redemption control. Recheck the listing if a previously valid code stops working.