There are many types of jobs that can be done by non-professionals, so called do-it-yourself people. Often these jobs require very little education or instruction (as in read the directions on the box). You read the directions on the box and TA-DA! You assume you are a mold testing expert. But without proper knowledge, instead of running, you could be just spinning your wheels by gathering useless information.
These kits usually contain some sort of Petri dishes that are to be set out in various "strategic" locations for a set period of time and then sent to a lab for culturing. The lab will then send you a report of its findings. The findings will tell you that you have viable mold spores in your house and will give you some of the types present. Surprise! Of course you have mold spores in your house. Mold spores are everywhere.
If you want to find out if you have a mold problem, you are better off hiring a professional to perform an inspection and to do testing that is appropriate to the situation.