Michael's Changing Fantasy Suit is an older product for use with Millennium Man 1 (Michael 1) and Michael 2.0. These instructions assume standard installation for DAZ Studio and the product.
In DAZ Studio, go to FILE --> Import.
Then browse to the .obj file itself
c:\Program Files\DAZ\Studio\Content\Runtime\Geometries\Anton's People\MCFS\Helmet3.obj
Now you should see it in the scene. It's all white.
To add the texture to it, do this. Go to SURFACES TAB. Then click on 'Helmet 3.' Now go to diffuse and click the arrow to the right. Choose 'Browse' and find this file and select it.
You can save the helmet as a preset in DAZ Studio so you don't have to do that again.