Once you download the files leave them as Zip files and just go to System, Settings and Add Ons.
Then choose Install from Zip File
Or rather than install you can go to System, File Manager and Add Source and enter
http://fusion.xbmchub.com you can get sports devil from here.
I found superrepo.org you can down load most repositorys which include the add ons and then just go through option 1 installing from zip
Then you have to go into add ons and install each add on individually.
Hope this makes sense just trying to get my head around it all myself