A challenge cache requires that geocachers meet a geocaching-related qualification before the challenge cache can be logged. This means that logs for this cache that do not meet the requirements will be deleted without further notice!
So, what do I have to do to make a proper foundit log???
Well, it's really simple! You just have to have found and logged at least 300 Multi Caches!
As a proof you qualify for this challenge, you join a screenshot from your finds to your log!
NOW GET OUT THERE AND COMPLETE THIS CHALLENGE... 
N.B. At first I wanted to publish a challenge where you had to fulfill the requirement that at least 10% of your logged finds should have been multi caches, but unfortunately this requisite is against the guidelines for challenge caches in effect! As I nevertheless wanted to reward cachers who, same like us, enjoy going the extra mile and are doing multi caches as well and are not only going for the quick statistic point this is now what remains of my initial idea!