Here's some examples of common DIY attempts at AC mats that are not effective.
None of these will give any real airflow to create a moisture barrier between the floor and mattress and as a result won't really reduce the condensation and keep the moisture out of the mattress which is what will turn into mold and mildew and stink.
Even the perforated mat won't be effective. While it looks like it would have airflow through the holes, when it is on the floor of a tent it is creating a seal around every one of those holes so no air can get through all of those holes.
In contrast as you look at the Tepui mats, you can see that the overlapping weave of the mat allows for a significant amount of airflow. It's also important to note that a mat that is somewhat stiff is also key. Anyone that has seen the Tepui mats first hand will know that they are pretty rigid and will not collapse under the weight of tent occupants. As a result the airflow isn't compromised at all from the weight of people. DIY solutions that use a foam type mat or something that can collapse or compress with the weight of occupants will not be as effective.
Here's the Tepui mat again for comparison.