Imac - Sony. Easy step by step instructions

I have an iMac 10.7.5 and have recently purchased a Sony blu-ray home cinema system for my Sony TV. Having searched for several days I was recommended to download Serviio, which I have done and it works, but really need very simple step by step instructions regarding adding photo and video files correctly. I know very little about computers. I have managed to get the TV and Blu-ray and iMac wirelessly connected . I can view my pictures and some home videos using Serviio but not being computer literate I would appreciate some very basic instructions, i.e. how to download properly and create correct 'paths' etc. Thanks