ideal standard dual flush toilet problem?

Well, I followed the advice given here to get the top of the cistern off, removing the two flush buttons in turn, then unscrewing the white plastic screw to get the cistern lid off.
NOW how the H**** do I put it together again?????
Obviously(?) the first step is to replace the cistern lid, then locate and re-fasten the white plastic screw. But as far as I can see, after many attempts to line the screw and it's destination up, that's not the (whole) problem (although that IS going to be difficult!) - something appears to have moved, although I can't see what, and the screw no longer apears to reach the threaded bit!!!! OK, I'm an idiot, but what on earth have I done, and what do I need to do to fix it?