The first three pictures are without the details to better understand the construction,
The blue pencil shows the mistakes I made:
Here show the red pencil my mistakes:
After two tests I should draw the details,....
....but I thought it's better to trace the construction and draw the details on seperate paper, that it's easy to see how I use the constructions.
After I finished these drawings Jose took a look to see each mistake I made, just like in this finished drawing: me - red