"So Kodi is the program right, and what kind of box can it run on? "
This is from their website:
"Kodi is available as a native application for Android, Linux, Mac OS X, iOS, and Windows operating systems, running on most common processor architectures."
Typically the 'android boxes' you originally asked about come pre-loaded with kodi - unfortunately as my friend discovered, it is often an outdated version so step 1 with these boxes is often to update to the newest version. The other thing to keep in mind is this - again from their website:
"IMPORTANT:
The official Kodi version does not contain any content whatsoever. This means that you should provide your own content from a local or remote storage location, DVD, Blu-Ray or any other media carrier that you own. Additionally Kodi allows you to install third-party plugins that may provide access to content that is freely available on the official content provider website. The watching or listening of illegal or pirated content which would otherwise need to be paid for is not endorsed or approved by Team Kodi."
As I mentioned - as a media player Kodi works quite well as is. For streaming however - you need to have those 3rd-party plugins. This is where 'the fiddling about' comes in. Some boxes come advertised as having many of these plugins pre-installed - others advertise ongoing support in this area but typically you have to pay more for the 'box' when you buy from them and who knows how good their support actually is?
I think 'americanaudiophile' has made a very good suggestion. Download kodi (it's freeware) to your pc and play around with it to see how well it works with your network connection etc. Be prepared to spend time loading in add-ons and chasing streams that do not actually seem to be there. Having said that, I tried it last night and did end up watching some usopen tennis on my laptop - it was quite alright. Oddly, I found it hard to exit the program - maybe there is a trick to this I don't know about.