Create a level area with a hired mini excavator (around $350/ day) or hire an excavation contractor. Stockpile soil for backfilling behind retaining walls (in Step 6)
Install retaining wall posts. Put a post at each end of walls and space posts 1.2m apart to match sleeper lengths. Dig 600mm-deep holes for each post. Concrete end posts first. Run stringline between them to line up posts in between, before concreting remaining posts.
Install floor supports made up of 2 sleepers laid on edge. Top of supports should sit 475mm below height of retaining walls. Space floor supports every 1.2m to match sleeper length. Make sure they’re level along their length and with each other.
Chamfer edges of floor sleepers, lay on and across floor supports and screw down. Lay sleepers so gaps between them are uneven. Cut 900mm-dia. circle in middle of sleepers for fire pit. Support cut ends.
Cut off top of posts to desired height and screw retaining wall sleepers to posts. Stagger joins between rows of wall sleepers. Screw wall capping to top of retaining wall and down any visible ends. Build step.
Apply decking oil to hardwood as recommended and let dry. Use river gravel to fill gaps around and under floor sleepers. Backfill behind retaining wall with soil (from Step 1) and roll out turf as required.