After purchasing the Iceland BIKF Airport on Simmarket, installing the second file, z_BIKF_mesh_xp12 (Xometry), is straightforward. Locate the downloaded file and simply copy it into the "Custom Scenery" folder within your X-Plane 12 directory. This folder typically resides under your X-Plane 12 installation directory, often found in your "Program Files" or "Applications" folder, followed by "X-Plane 12" and then "Custom Scenery". Once copied, restart X-Plane 12, and the BIKF mesh scenery should be automatically activated, enhancing your Icelandic airport experience. Remember, if you encounter any issues, consult the BIKF Airport documentation or contact the developer for further assistance.