Did you even try searching for this ?
Took exactly 10 seconds to find this video:
There are also a few forum threads that talk about it including on Seabreeze, just google: fixing naish octopus.
The first step is to locate your leak(s) which shouldn't be that hard considering you're loosing air in 30 minutes. Over-inflate your kite a bit (so it's easier to find leaks) and spray soapy water along the LE and Struts. Start with the valves as they are often the culprit. If you have a leak in the LE you don't always have to remove the whole LE to fix it, sometimes only half of it, sometimes (if the leak is close to the middle zipper or the wing tips) you can just pull out that area, fix it and put in back in without removing the whole bladder.
Christian