I'm havin trouble with my first infusion where iv got a tiny air leak sumwhere and I can't find it.

An ultra sonic detector is the best option.. Vac innovation do a good one. Dont get the ones they sell for car mechanics as it is not sensitive enough. BUT it can still be impossible to find some leaks.. The air tracks along creases or you just cannot find it.. But it is still worth having one if you lose a bag once in a while it happens but it gives you the best chance of fixing a leak.