: Right-click in the empty palette space and select Import Subassemblies .
[Download PKT File] │ ▼ [Open Civil 3D Tool Palette] │ ▼ [Right-Click -> Import Subassemblies] │ ▼ [Path to PKT File] │ ▼ [Add to Tool Palette Tab] Civil 3d Subassembly Pkt Download High Quality