RB-05Fix the brackets for your ceiling typeTimber joist: drill a 2-3mm pilot hole into the centre of the joist and drive a 40-50mm No.8 wood screw through the bracket. Metal channel or metal stud ceiling: never use a plain wall plug or wood screw, they strip straight through 0.5mm steel — use a self-drilling metal-stud fixing sized for the bracket. Plasterboard only, between joists or channels: use a toggle-type hollow-wall anchor rated for the blind's weight plus a margin, since the constant tug on the chain works ordinary plasterboard plugs loose over time. Solid concrete or masonry soffit: drill with a 6-7mm masonry bit to 35-40mm depth, insert a matching wall plug, then drive in the screw. Lath and plaster: find the joist behind the laths as for timber, score the plaster first with a bradawl to stop it cracking, and use a slightly longer 50mm screw to bite past the laths into solid timber. If your marks fall on plasterboard between metal channels with nothing solid behind, fit a timber batten screwed across two channels, or fix through to the structure above, rather than relying on the plasterboard alone.