OK first you should read completely through the instructions before starting the building process, It's a good habit to get into while becoming a model builder. I've built prob. 25 planes and still do this , even with the most basic kit's.Anyhoo, run the spar's out past the last rib, at wing tip, to be cut off later. Don't cut them individually, wait till there all glued and take a razor saw and cut them all at once, there's a ply end cap that covers the end of the rib, make sure to sand the left over spar 's flush with rib. Now, at the trailing edge.use a straight edge if you need to , but it's easy to just free hand with your razor knife(use a new blade). don't concern your self with a perfect cut, leave a bit to sand flush, The sheet material is soft and will sand flush with trailing edge very easy (USE A SANDING BLOCK).always CHECK THE BOX ON THE INSTRUCTION MANUAL AFTER YOU FINISH THE PROCEDURE. The ones that are for wing building have 2 boxes, At the end it will say to repeat process with other wing. you have planes and instructions, there's no need for pictures of both wing halves in the manual. good luck and happy flying. Buz^