The templates can only be opened and edited with Adobe After Effects. Check the description on each template to see what version of After Effects can open the project - most are compatible with version CS3 and up.
Sometimes contributors will include basic instructions in a ReadMe file, but if you run into specific problems or have any questions, please contact our support team. We cannot guarantee that we can resolve your issue because we are not trained in After Effects, but we will certainly do our best! If we can’t, we recommend searching the Adobe support forums for After Effects, as someone else may have encountered the same or similar issue and found a solution.