I have tried three different pathways into getting started with the XSI Mod Tool and have run into nothing but endless frustration and hassles.

First I followed the "Hello World" tutorial until Mod Tool wouldn't display "Model" in the menu bar when it was supposed to.  Dead in the water.

Then I was following another Mod Tool tutorial which was fine until I was supposed to set "Texture Space" to a certain selection, but "Textured Space" was disabled.  Dead again.

Then I downloaded XNAGSE.6.02.xsiaddon and there were no instructions with what to do it when it was downloaded.

And I cannot map a lot of what I see in their documentation to anything I see on my screen, such as following the XNA GSE Integration Help.   I see words and images on the page but I don't know what they left out but whatever it is it is essential to understanding what they are talking about.  Stuff doesn’t appear where it is said to be, etc.

Far from having a brain-dead tutorial in a single location that is bulletproof, which is what I would like, I am left with just a chaotic mess that goes on for as far as the eye sees and fails before any proof of any usefulness of the Mod Tool can be demonstrated.

For some reason the older ModTool/XNA guide didn't mention it, but to get that "Model" button you need to change to Render Mode.  In the toolbar on the left side of the screen, change it to “Render” mode by clicking on the purple button on top that says “Model” and then click on “Render”.

Also...I don't know if you've seen it but I did write up a simple for tutorial for getting ModTool working with XNA.  It's more of a programming-oriented guide, but it does go through the basics of setting up ModTool, connecting it to a project, and making a very simple model.  The link is in my sig.