Turn the centres of the turnbuckles at the top fixings. Turning them to the left should tighten the turnbuckles, however this may vary, so check that...
Step 3: Fit the wall fixings
Drill holes at the fixing points that you marked and install the screw eyes. If drilling into masonry, this will require a 7mm diameter plastic plug to fit the screw eye. Check that your plug fits the screw eye before installing.
Hang your turnbuckles from the screw eyes as shown.
Bio:I am a freelance design engineer and drummer. My business site is at http://www.zero-waste.co.uk and is often concerned with appropriate technologies, open source design and design for sustainability.