The first thing you should do is to find the leaks and determine if there are small puncture holes in your Leading edge bladder/ strut bladders or if you have leaking valve(s) ?
Overinflate your kite (i.e. 10 PSI) and spray soapy water everywhere around the bladders and valves and locate the leak(s). If you have a pool that's even better for checking for leaks. This is the easiest part of the process and takes no more than a few minutes! If you have big leaks(s) that's easy to find, however if you have very slow leaks that's harder to find, hence why it's easier if you overinflate the kite to be sure you find the really small leaks.
If air is leaking around one or multiple valves that's usually bad news and could be a sign that you need to either replace the faulty valve(s) or get a new bladder in. For those jobs it's worth contacting a professional repairer to make sure they have the replacement valves or bladder. These parts can be hard to find especially if your kite is more than a few years old. Usually when valves fail it's a sign that they may all fail, which ends up being costly repairs and sometimes not worth it.... that's what a leaking valve looks like
If air is NOT leaking around any valves, then that means you have either one or multiple small puncture holes somewhere in the bladder and that's a fairly simple fix which you can do yourself, it just takes time and patience especially if you need to remove the Leading Edge bladder entirely and put it back in.
That's what a leak in your strut bladder looks like
That's what multiple leaks in your leading edge bladder looks like
All you need is some Tear Aid Type A, watch some how to videos such as the one below and anyone can fix it themselves.
The hardest parts are finding the very small leaks once pumping the bladder outside of its casing and putting the leading edge bladder back in without any twists, just be patient and take your time :)
Christian