To install the Wisext tools you have 3 options:

1. SketchUp Extension Warehouse

The Wisext tools are now available on the official SketchUp Extension Warehouse:

You access to that library directly from SketchUp by clicking this button:

  or  

You don't need to install each tool. You install one and you can activate the others by selecting in the menu:

Extensions > Wisext > Activate extra tools

We advise updating the plugin to get the most recent version of all the tools: 

Extensions > Wisext > About update

 

2. Installing a .rbz file

SketchUp installs the plugin if it is zipped in a .rbz file. You can get it here.

From SketchUp 2017, open the Extension Manager and click "Install".

 or 

3. Windows installer

You download a .exe file installing the plugin. It works only for windows.

You get it here.

Security warnings with .exe installer?