This documentation is written in a development version.
Since this asset was created with the assumption of adding shape keys to clothing, the application instructions are based on adding shape keys to clothing.
Video: @jaewoon_VRC
Video_3060757b-47a2-4d59-a36c-50d73fbd6d5c.mp4
Right-click on the Clothes mesh object and click the Add PullUpTool button to add the prefab.

Place the clothing's chest bone inside the object's mesh bone.
Place the Avatar's Chest bone at the handle reference position.
Place two bones for each end of the avatar's chest in the Handle Positioning object.
Enable the Shape Key preview to see how it transforms and make adjustments to the object position, angle, and scale.
If you are going to change the animation type, make sure to read the description for each component field to see what it says about the animation type.

This image shows a simple setup as described.