The plugin is packed with "parametric-style" tools, meaning you define the parameters (like wall thickness or stair height) and the tool builds the geometry for you. Wall & Opening Creation
Click Install Extension and select the .rbz file you downloaded, or search for "1001bit" directly in the Warehouse. sketchup plugin 1001bit
While not a full topography tool, 1001bit offers practical site features: The plugin is packed with "parametric-style" tools, meaning