To install on your operating system refer to the manual https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Libraries

Three steps are necessary to use this library:

1. Define an inch as a variable. This can be any number, it’s used as a base to calculate other values such as `ft`.
2. Include the library.
3. Instantiate an object.

meter=100;
m_to_in=0.0254;
inch=meter*m_to_in;

include <openscad_wood/lumber.scad>;

board(2,4);