Once installed, a new toolbar titled should appear.
The extension is primarily marketed to structural engineers and designers for reinforcement detailing in SketchUp. Toh Rebars V1.2.0 Extension For Sketchup Download
You can download the Toh Rebars V1.2.0 extension from the SketchUp Extension Warehouse or from other online sources. However, be sure to only download from trusted sources to avoid any potential security risks. Once installed, a new toolbar titled should appear