designing a device for animal

I'm hunter. see the images: [login to view URL] [login to view URL] You should create something similar to that images. Creates it in CAD file(using CAD software Windowsxp compatible, send me the software download link). Provide the assembly instructions ... in my country, I hire a company(metallurgic, ironmaster) to manufacture the parts.(takes 25-40 days to get everything ready.) escrow release: 10% design approval 30% CAD software, CAD files(individual parts) and assembly instruction.(step by step with images). 60% real test.(after I buy the parts and assemble in my country). note 1: no welding is NOT required, BUT it would be interesting build using only screws/nut. note 2: I want a software which can increase or decrease the size of the device and automatically provide the metric proportional to each piece.