Where do you start?

I have 2 xbox 360 machines and would like to know where do I began, I once had my friend mod an old xbox and had it for couple years and really enjoyed but it had gone bust so I figure I try this myself on the 360.

Can anyone point me to the right direction?

Best regards !

Welcome to the site! This section should help a lot: https://www.horizonmb.com/forums/125-Horizon-Tutorials