Start at the Entrance Campsite: turn the wheel before crossing the water, then follow the ceiling pipes to reach the hammer. Most of what comes after depends on that tool: locked doors, resource runs and camp stations. The recurring sticking points are the forge's upper lever, clay deposits labeled Goop pile, and carcasses that need processing before cooking. Pick whichever one you're stuck on.
Open New Routes: Hammer and Forged Keys
Follow how to get the hammer to cross the water passage, climb the pipes and drop into the barred room. Bring a torch and leave inventory space for the pickup. The hammer breaks rusty metal fences and opens passages near the water and upstairs.
For locked doors, follow the prison, iron and Jaguar keys. Supply coal and scrap metal at the forge, then operate its upper lever for the iron key. The Jaguar key needs three pieces; finish them before returning to the Jaguar door for the silver dagger.
For the whole route in order, see the walkthrough.
Gather Smelter Materials: Pickaxe to Sewer Clay
Get the pickaxe before making a clay run. After entering the prison, take the stairs beside its entry stairs farther down and open the door below. Bring an iron rod and watch for skeleton archers above.
Then follow how to get clay: return to the sewers and mine deposits labeled Goop pile. Target the piles themselves rather than ordinary ground. Bring the clay and scrap metal back to camp to build a smelter.
Build a Workbench: Save Leather and Iron Rods
Follow how to get iron rods for the spider-area chest or the camp smelter route. The chest contains two finished rods; the smelter takes scrap metal and coal. Save two rods for the workbench if that is your next craft.
For the other material, follow how to make leather. Your first leather comes from chests, then build the workbench with 1 leather, 2 iron rods and 3 wood planks. At the workbench, turn animal hides from rats into more leather.
Prepare Food and Clear Roots: Cooking Table and Axe
Follow the cooking table when whole carcasses will not go on the rotisserie. Craft the cooking table from 2 wood planks and 1 leather, then process bat carcasses into drumsticks and scorpion carcasses into tails. One raw meat becomes three raw steaks at this station.
If roots block your next passage, follow how to cut roots for the axe route. Continue through the spider prison into the sewers, go past the slime, and use a grappling hook on the cranks to lower the water. Search the crypt-like area beyond for the axe, then return to clear the roots.