Timing belt change Megane 1 1.4 16V

Dear people! I have to do the timing belt + WaPu at my convertible in 2001, 1.4l 16V. Camshaftlineal + crankshaft fixation spine; lift platform and other tools are available in the hobby workshop. Have done this before at the Ford, so I’m not a newcomer for 16V engines… So, and now the question: In the Contitech instruction on the timing belt change it says: “Absolutely block the crankshaft when loosening the belt disc screw with suitable screwdriver!” (NOT with the fixing thorn, can abort, serves only for setting) Nice and good, but where to put the screwdriver ?? Sure, flywheel gearing. But where is the accessible ? From above I see nothing, except the opening to the OT-gender at the gear box. Where is the screwdriver used to resist ? Thanks for information !! Best regards, Thomas