A solid starter workbench is 180cm × 60cm × 90cm tall. You need 4 legs from 90×90mm timber, a 40mm thick top (laminated pine or MDF), and 45×90mm stretchers for the base frame.
Cut the stretchers to length and join them into two H-frames (front and back). Use mortise-and-tenon joints or pocket hole screws. Connect the two frames with the four legs.
Cut plywood to fit between the bottom stretchers and screw it in place. This provides tool storage and rigidity.
Place the worktop onto the base and attach from below with screws or metal brackets. Ensure it overhangs evenly. Check for level and shim legs if needed.
Sand the top with 80 then 120-grit paper. Apply two coats of Danish oil or a penetrating sealer to protect the work surface from stains and moisture.