No runway slope or wind given in the question so you just draw straight up through both reference lines until you get to the flap reference line.
So start at 2400m on bottom of graph, proceed up to flap position ref line and move up and right to 15* position then draw line straight up.
Coming from OAT of -10 proceed up to 7000ft, then right to the ref line and then interpolate towards the line previously drawn then right to 56,000