Hi ingoenius, have you tried it yet?

If you are having difficulty with a particular part of the model, please upload what you currently have and that will help me give you some ideas on how to make progress.

The basic procedure to build something in MoI will be to start drawing some curves and constructing surfaces. MoI does not have the entire Catia toolset though, so sometimes you will need to use alternate ways rather than what you see in the Catia tutorial. For example, you may need to construct surfaces and then use the Fillet function to make a smooth juncture between them, for an example see my previous post here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2505.2

Also check out these MoI video tutorials: http://moi3d.com/1.0/docs/tutorials.htm which give you an overview of how to construct objects in MoI, starting by drawing curves to make surfaces and components, then using booleans to combine pieces, and fillets to round off sharp edges.

- Michael