I just want to make sure you have found the documentation for Form Builder. All the docs for the product can be found at css-form-builder/.
The Getting Started Guide begins with a section titled 'The WebAssist Menu' to introduce to our users the new access point we will be using for our extensions going forward. Since many of our extensions do not insert anything to the page, the Insert menu is not appropriate and this better exposes access to our extensions for new customers.
There are also a number of How Tos to guide you through using the other tools that are integrated into the product. The access points in those tutorials should all be correct.
If you find any reference to incorrect access points please let us know so that we can fix it immediately.