Jtags are very easy to add files/patches.
First - Do you have a patch for a game?
Second - KV, You need a kv, microsoft now has control over dashboard activity. (when you connect to xbox live, KV starts ticking)
Third - You need a transfer cable. Usb might not be good enough
Put xex on your desktop, inject all files need,
Its pretty simple once ur files are done.