LibreCAD is a free Open Source drawing CAD application for Windows,Apple and Linux. LibreCad Computer Aided Design (CAD) application for 2D design. I find this software ideal for creating technical drawings in 2D design works simple and there are many videos online to help you get started.
See this video to get a idea how its works
LibreCAD is a fully comprehensive 2D CAD application that you can download and install for free.
Operating Systems: Linux, Mac OS X, Windows 7 (32 bit), Windows 7 (64 bit), Windows 8, Windows Server, Windows Vista (32 bit), Windows Vista (64 bit), Windows XP