It seems perhaps that you didn't quite complete your question since I'm not quite sure what you are asking is to be installed on top of what? These interlocking tiles are designed to be laid over any hard surface such as concrete and they simply lock together without any fixing devices etc.

Or if you were referring to what treatment may be required on top of the tiles then we simply recommend a good quality decking oil to be used every 12 months or so to keep them in good condition and to slow the rate of fading due to the UV in sunlight.
But if I didn't answer your question correctly, then please re-submit it to Houzz